Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1] 2   Go Down

Author Topic: Using finishing epoxy for the first time  (Read 616 times)

clockworks

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 86
  • Model Boat Mayhem is Great!
  • Location: Cornwall
Using finishing epoxy for the first time
« on: May 21, 2019, 05:33:10 PM »

I'm building my first RC boat kit - an Aeronaut springer. I've got 3 more kits ready to start, but I thought I'd build something relatively simple first, and practice some of the techniques that I'll need to use on the more complex kits.


Something that's probably not essential for the springer, but will be needed in future, is finishing the hull with epoxy and glass cloth. I bought some Z-poxy and lightweight cloth, along with some polyester resin and mat for beefing up the inside around the propshaft/keel. The inside is a bit messy (but solid), and I discovered that glass mat doesn't really "do" corners. I've not worked with GF and resin since I built a Westfield kit car 30+ years ago.


Struggling a bit with the GF made me read through a lot of posts on here before I started on the outside of the hull. For sharp corners, the best way to work seemed to be in sections - lay the cloth slightly oversize on an area, wait for it to cure, trim the edges back, then lay the next section?
I figured I'd do the smallest panel first - the transom - just to get an idea of how epoxy works. Once that's cured, the bottom of the hull & bow, then the sides.


Does that sound like a good plan?  I hope so, because I've just done the transom. Brushed on the epoxy, laid the cloth, waited for it to "wet out", then gently over the surface with a credit card. Seems to have gone OK.


My question really is how to tackle the bottom of the hull. I assume that I can do the front panel at the same time without the cloth lifting off the plywood? What do I do about the keel/skeg? Lay the cloth in one piece, with a slit cut to go either side of the skeg, or in 2 pieces?


For the skeg itself, do I try and use cloth on that (one piece or 2?), just brush on some epoxy with no cloth, or just use a few coats of sanding sealer? I've already run a fillet of tube epoxy between the bottom panel and the skeg, and around the prop tube, so it's pretty solid.


Like I said, I probably didn't need to use epoxy and cloth on this kit at all, just want to get the hang of working with it before building my Boothbay lobster boat. I really don't want to mess such a nice kit up by practicing new things on it, so the next build will be an Aeronaut Mowe 2. A bit more complex than the springer, but still relatively flat hull surfaces.
Logged

DaveM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 187
  • Why on earth do I do this?
  • Location: Nottingham
Re: Using finishing epoxy for the first time
« Reply #1 on: May 21, 2019, 06:20:29 PM »

This might be of use to you https://www.modelboats.co.uk/news/article/finishing-and-sealing-of-wooden-hulls/18771

I think it's also somewhere on Mayhem but that's incidental. Don't mix finishes e.g. sanding sealer and epoxy. Wetting the surface before laying the cloth on can be a pain if you get wrinkles in it, because you're bound to open the weave of the cloth by trying to lift and reposition it. The Spraymount trick has worked well for me since I began using Z-Poxy a long time ago.

Also don't go for the very lightest cloth for much the same reason. I use the 34gsm De Luxe Materials stuff and it's just the job. I covered my Midwest Lobster Boat hull in three pieces; one each side from the keel to the gunwales and the third on the transom. Note that the manual specifies two thicknesses of the cloth supplied - that works fine.
Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #2 on: May 21, 2019, 06:38:02 PM »

Great advice Dave I will be asking questions this weekend O0


For my recent Lobster rudder which is only a small flat area I found that dots of superglue worked effectively to secure the cloth. This was in the instructions.


 

Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

clockworks

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 86
  • Model Boat Mayhem is Great!
  • Location: Cornwall
Re: Using finishing epoxy for the first time
« Reply #3 on: May 21, 2019, 06:58:54 PM »

Thanks for the link - clears up most of my questions/issues. I'll get some spraymount, that sounds like it'll make life a lot easier.


The cloth that I have is 17gsm, which is quite fragile. I'll get the next weight up on my next order for future builds.


I've got a big can of 99% isopropyl, which I think is the same as rubbing alcohol?  Does this also work for cleaning epoxy from brushes and scrapers? I used acetone today for cleanup, didn't thin the epoxy. I suppose I could just use cheap brushes and bin them, but I didn't want to risk loose bristles getting stuck in the job. I'm using a Harris 1" synthetic brush, which I didn't get on with for decorating, but seems to work well with epoxy.




Logged

clockworks

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 86
  • Model Boat Mayhem is Great!
  • Location: Cornwall
Re: Using finishing epoxy for the first time
« Reply #4 on: May 21, 2019, 07:00:02 PM »

Great advice Dave I will be asking questions this weekend O0


For my recent Lobster rudder which is only a small flat area I found that dots of superglue worked effectively to secure the cloth. This was in the instructions.


Did you do both sides with one piece of cloth wrapped around the rudder?
Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #5 on: May 21, 2019, 07:07:15 PM »

Yes :-))
I veered away from the instructions though in that I did not round off the edges first.
I clothed and resined before trimming the edges back to square then rounded off before applying second coat of resin



Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

clockworks

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 86
  • Model Boat Mayhem is Great!
  • Location: Cornwall
Re: Using finishing epoxy for the first time
« Reply #6 on: May 21, 2019, 07:13:59 PM »

Thanks. Good to know that it'll lay OK around the edges

Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #7 on: May 21, 2019, 07:25:46 PM »

I buy these in bulk for best price
These rarely lose a bristle
https://www.nexusmodels.co.uk/great-planes-3-8-10mm-disposable-epoxy-brush.html
Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

DaveM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 187
  • Why on earth do I do this?
  • Location: Nottingham
Re: Using finishing epoxy for the first time
« Reply #8 on: May 21, 2019, 07:34:39 PM »

I-PA (aka rubbing alcohol) is a bit expensive for cleaning up! I buy a 5L can of Standard Thinners from our local motor spray shop - about £9 once every three years - and use that for cleaning up just about everything.  I also use cheapo brushes but, being 50% Yorkshire, I can't bear to throw them away after just one use. Even squeegeeing off the surplus resin brings tears to my eyes... What a waste. You'll find that thinning the epoxy about 10-15% makes it a lot easier to apply and scrape off again, and you'll be throwing away a bit less expensive resin on the kitchen roll mop!

I tried the trick of using dots of superglue to tack the cloth along the keel line but found it left hard little lumps, so I reverted to the Spraymount technique. Helluva price but it works for me.

DaveM
Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #9 on: May 21, 2019, 07:45:58 PM »

Is the spray mount applied to the cloth after itís positioned ?


Cancel that  :embarrassed:   Better to read your link  O0
Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #10 on: May 21, 2019, 08:57:13 PM »

Thatís in my favourites now thank you  :-))
Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

Tug Fanatic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,322
  • Location: England
Re: Using finishing epoxy for the first time
« Reply #11 on: May 21, 2019, 09:05:53 PM »

Is 3M77 at around £17 really better than all the other repositionable spray adhesives which cost from around £4 on Amazon?
Logged

DaveM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 187
  • Why on earth do I do this?
  • Location: Nottingham
Re: Using finishing epoxy for the first time
« Reply #13 on: May 21, 2019, 11:17:44 PM »

Is 3M77 at around £17 really better than all the other repositionable spray adhesives which cost from around £4 on Amazon?
I really have no idea. The can I have says '3M Spraymount' on it and Googling that name will reveal many sources, most of which seem to be less than £17. I do know that it works fine for me every time I use it. If you do find an alternative on Amazon then please let us know what it is and maybe I'll get some when this can finally runs out. At the current rate of use that will be sometime around 2028.
DM
Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #14 on: May 22, 2019, 08:17:00 AM »

Interesting
Weíre did 3M77 raise its head  %%
Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

Tug Fanatic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,322
  • Location: England
Re: Using finishing epoxy for the first time
« Reply #15 on: May 22, 2019, 08:28:43 AM »

Interesting
Weíre did 3M77 raise its head  %%
Er yes. I have heard of 3M77 being used & I thought that it was Spraymount but apparently they are not the same product.

3M77https://www.amazon.co.uk/3M-Super-Multi-Purpose-Spray-Adhesive/dp/B002BB9A4S/ref=sr_1_1?keywords=3m+77&qid=1558510004&s=gateway&sr=8-1

3M Spraymounthttps://www.amazon.co.uk/3M-SprayMount-Adhesive-Spray-Transparent/dp/B000SHR4ZE/ref=sr_1_4?keywords=3m+77&qid=1558510004&s=gateway&sr=8-4
Logged

clockworks

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 86
  • Model Boat Mayhem is Great!
  • Location: Cornwall
Re: Using finishing epoxy for the first time
« Reply #16 on: May 22, 2019, 08:44:18 AM »

I've ordered some 3M spraymount, 2x 400ml cans for £23.99 on eBay. Also some 35gsm cloth.


I'll keep an eye out for some of those Great Planes brushes.


I've been using isopropyl alcohol for years as a general cleaner and degreaser when working on clocks. I buy it in 5L cans, and decant it into a smaller bottle. I like it because it's not too flammable (can have a ciggy in the workshop without setting fire to myself!), doesn't smell too bad, and doesn't irritate my skin. Not keen on using thinners indoors, but appreciate it's cheaper.
Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #17 on: May 22, 2019, 09:10:17 AM »

Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

boaterjim

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Model Boat Mayhem is Great!
  • Location: gainsborough
Re: Using finishing epoxy for the first time
« Reply #18 on: May 22, 2019, 09:22:45 AM »

Top Tip, apply cloth using De lux meterials Eze-coat, Ebay. Its water based so no mess or thinners .
You can then either epoxy, using stiff card spreader or carry on with the Eze-coat.
Safe no fumes easy clean win win id say :-)) :-)) :-))
Jim
Logged

mrzippy

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 109
  • Location: Leicester, Midlands
Re: Using finishing epoxy for the first time
« Reply #19 on: May 22, 2019, 11:20:29 AM »

Hi Guys,

I have used West Systems, SP Systems and recently Easy Composites (cheaper/slower setting options) epoxy resins
and lightweight glass cloth over the past 40 years + as the base coating to finishing large balsa glider fuselages and
balsa/ply boat hulls etc, followed by Halfrauds aerosol paints.

I think its wonderful stuff giving a firm foundation soaking into into the wood, stiffening the surface especially when used with cloth,
once dry and flatted down you have a great surface to paint or use as a clear gloss coating over wooden planked decks etc,
this can be burnished to a high gloss finish with the cloth disappearing beneath the resin.

My favorite weapon of choice for applying glass cloth is a mini stiff foam roller (usually sawn in half to make it more manageable)
I quickly roller on a coat of epoxy, then drape the pre cut glass cloth onto the wet surface, roller over to lay the cloth out and it goes on
perfectly without Spraymount etc and disappears into the resin, depending on what weight cloth you use.

Rollers allow you to push very fine cloth around corners, I have wrapped a complete large scale glider fuselage using one piece of
lightweight cloth to cover the whole model in one session, forcing the cloth around the complex 'egg' shaped fuz with a roller.

Very lightweight (0.9oz per sq.metre) will disappear into a single application of resin (check my Swordmans deck at Mayhem this weekend).

Recent experience with slightly heavier Easy Composites 100gm cloth requires a second coat of epoxy to fill the weave,
applied while still 'Post It Note' tacky to prevent blushing.

Having related the above about the wonders of epoxy resin - I am in the process of finishing a small free sailing solid balsa yacht for this weekends event
using Wilko's water based floor varnish (aka. EzeKote?) to apply fine glass cloth and it worked very well.
Simply applied by a soft half inch flat artists paint brush the hull covered in one piece nice and flat, no wrinkles,
will be interesting to see how it stands up to the test of time and dings etc, certainly a much cheaper option,
easy to apply, cleans up with water and no nasty fumes.  regards Paul
Logged

RST

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 389
  • Location: UK
Re: Using finishing epoxy for the first time
« Reply #20 on: May 22, 2019, 06:41:12 PM »

Interesting statement before about smoking round chemicals which I think needs taking with a pinch of salt.   Most if not all the alcohol/solvents mentioned carry explicit warnings on the MSDS sheets regarding fire, and there should be the regulatory CLP pictograms on the suppliers cannisters.  I'm a smoker myself, but never around solvents or alcohol (unless its the pub beer garden).  2 reasons: fire, and smoking is a very easy way to transfer contaminants from your fingers to your mouth.


A few years ago now I politely suggested to someone that smoking on a garage fourcourt right opposite a couple of cars filling up might not be a great idea.  I was chased into my own car and threatened!

Wasn't that long ago I started using the little bottles of hand sanitisers.  I made a schoolboy error of using some gel and when my hands were dry (or so I thought) I lit-up a cig.  I din't have to worry about plucking any nose or eyebrow hairs for about 4 weeks after.  Silly mistake of course.  Duuh!!

Just saying because not everyone, particularly beginners are aware of the hazards of some modelling products.  They might come in small bottles, but actually some of them can be quite dangerous.  I'm not meaning to be patronising, but when your tub of stuff says flammable, toxic, poisonous or irritant etc, please heed the warning if youre a beginner.


Rich
 
Logged

Taranis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,325
  • Kirklees MBC/ Balne Moor MBC
  • Location: Yorkshire
    • Shannon builders group
Re: Using finishing epoxy for the first time
« Reply #21 on: May 22, 2019, 10:29:53 PM »

Accepted £5.01 so £8 delivered
https://ebay.us/BAXvku
Logged
ANDY

Happy modelling since Jan 2017
My Portgarth https://www.modelboatmayhem.co.uk/forum/index.php/topic,57583.0.html
Shannon builders group (non public) http://www.shannon.clwydpark.co.uk/index.php

mrzippy

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 109
  • Location: Leicester, Midlands
Re: Using finishing epoxy for the first time
« Reply #22 on: May 23, 2019, 09:51:04 AM »

A quick note about setting times may be of interest - I've found West and SP resins WILL set off in their recommended,
short, around 15 minutes working time - requires one to get a wriggle on before things starts heating up and setting !

The heating up is real folks - early experiments with West resin - I used too much hardener in a mix,
minutes later the plastic mixing pot was smoking and eventually melted,
the heat generated by the catalytic reaction has to seen to be believed.

I've recently switched to using Easy Composites (Stoke on Trent) epoxy resins because -
a)  its a cheaper than the above + great next day service from helpful knowledgeable staff.
b) they provide a SLOW SETTING HARDENER option, which stays workable for up to an hour in cooler weather,
allowing you to take your time, possibly cover the whole model in one session !

Update re the floor varnish (ezekote) - FOUR coats applied and allowed a day to dry in a hot conservatory,
a quick sand down - sounded like playing a musical wash board,
varnish had not filled the cloths weave, coat of grey primer revealed the surface to be covered in pin holes,
not amused.  Paul

Logged

Tug Fanatic

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,322
  • Location: England
Re: Using finishing epoxy for the first time
« Reply #23 on: May 23, 2019, 11:28:07 AM »


...............................I've recently switched to using Easy Composites (Stoke on Trent) epoxy resins because -
a)  its a cheaper than the above + great next day service from helpful knowledgeable staff.
b) they provide a SLOW SETTING HARDENER option, which stays workable for up to an hour in cooler weather,
allowing you to take your time, possibly cover the whole model in one session !......................


not amused.  Paul

Which Easy Composites resin?
My ex supplier of West System has 2 different hardeners. I wonder if you have only tried the fast one.
Logged

Colin Bishop

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 9,993
  • Location: SW Surrey, UK
Re: Using finishing epoxy for the first time
« Reply #24 on: May 23, 2019, 11:39:39 AM »

Quote
Update re the floor varnish (ezekote) - FOUR coats applied and allowed a day to dry in a hot conservatory,
a quick sand down - sounded like playing a musical wash board,
varnish had not filled the cloths weave, coat of grey primer revealed the surface to be covered in pin holes,
not amused.  Paul

Not EzeKote then...

Colin
Logged
Pages: [1] 2   Go Up