Model Boat Mayhem
Technical, Techniques, Hints, and Tips => GRP & Epoxy => Topic started by: RWH on July 17, 2017, 07:15:59 pm
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I have read that it is best not to use epoxy for bonding wood to GRP hulls because it may distort the hull from the heat generated by the glue. If this is the case, then what adhesive do I use to bond wood to the side of my GRP hull?
Kind regards,
Bob
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Epoxy glue will not generate any significant heat in this situation, you have been misinformed. It is probably the best option for bonding the two materials but ensure that the GRP is roughened as the joint will be mechanical rather than chemical.
Colin
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Interesting as I have been stressing over this and I have seen more than one warning from reliable sources and one source was from a GRP builder of many types of model hulls. But I am glad to know this now I can continue with my build.
Kind regards,
Bob
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Used in large quantities the chemical reaction in epoxy can generate some heat but in the small amounts needed to construct models surface to surface you should have no problems.
Colin
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My hull is 45" long and I wanted to lay a 1/16" x 3" x 24" balsa strip on both sides and then glue my mahogany strips to the balsa. Would that size balsa strips generate too much heat?
Kind regards,
Bob
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good evening one and all :-)
just in my humble opinion - the only time heat is generated in Epoxy resin or Polyester resin is
a) When one has the mix ratio wrong i.e. too much hardener to the resin - this generally generates a certain amount of heat. This, if in a combined space such as a mixing tumbler where one has a large concentration of the mixture - this may, if its polyester resin, bubble & smoke ^ dissolve and melt the plastic container that it is held in. Also noxious fumes will emanate into the air.
b) Epoxy resin, depending on the type (as there are as we know several types of Epoxy for various applications) tends to do the same as above but can become slightly more toxic if it reaches this stage SO DO BE WARNED
If your mixture is correct though, and you have mixed it in small quantities and spread it over the area thinly - one should have no problem with heat generation.
The things to be cautious about are - the materials which are being bonded together - glass fibre and wood - one will generally have no problems bonding with the polyester/epoxy based resins. Time to worry is when you have certain plastic hulls and oily timbers such as teak/Iroko which we have to use special glues/treatments for bonding.
John
ps remember heat + smoke make man take action and run fast :-)
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Hi,
I have used Stablit Express for years never had a problem, I think it is branded under UHU now.
Regards,
Rich
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I stopped using epoxy a while ago.The construction industry now have a large range of adhesives which I have found fits most of our requirements. I recently bought a model and found the timber frame inside tbe hull had been glued using epoxy. The glue had gone very brittle hence the frame and plastic deck just came out of the hull. My thoughts on this matter only no wish to influence your choice of glue you use.
Stan.
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Stan
Can you name a few of the adhesives you use and have you ever used "no nails"
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HI Seaspray will post some info this evening.
Stan.
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Stan cheers
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HI Seaspray will post some info this evening.
Stan.
Yes we are all looking forward to that! O0 :-))
On a serious note I have not tried it because of the nastiness of failure but how good are the "no nails" type products for modelling?
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Hi Everyone,
Thank you for your replies and I am looking forward to your recommendation on the different brands of glass resins Stan. Has anyone here used
Milliput not for the timber siding but for the floor ribs? It would not work for the siding but should do well for the ribs. It takes about 24 hours to cure and it give off no heat and a very strong bond from what information I have received.
Kind regards,
Bob
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The ones I have used are Nail and Seal , Sticks like Sh t, and St ix all. . I used Nail and seal on my carrier to stick down plastic card to light ply way back in 2009 and it is still in place. Stix all to glue motor mounts and ply into a plastic hull. Like all adhesives if not sure then give technical a call. The above examples are not under great loads or stress. So if not sure make a call. I have no wish to change how our what you use to glue items in your project.
Stan.
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HI Bob the ones I have listed are not resin based products.
Stan
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Cheers Stan
I just used no nails on the caravan and it looks different from using it years ago also said it needed 24 hrs to fully set again unlike years ago it set in 10 mins
Muliputt I've bought 2 pkts first in the 80s and it was solid when I got it so it was a bin job Second one lately it seems to take a
time to mix and felt hardish So I've bought Alteco's EpoPutty this is to be used for making parts from a mould. I'll be using it soon on the Scotia build
I've still haven't used the hot glue gun for modelling
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I use gel coat to stick wood to glass fibre. It works for me all the time. Never had a failure. nemesis
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good evening one and all :-)
just in my humble opinion - the only time heat is generated in Epoxy resin or Polyester resin is
a) When one has the mix ratio wrong i.e. too much hardener to the resin - this generally generates a certain amount of heat. This, if in a combined space such as a mixing tumbler where one has a large concentration of the mixture - this may, if its polyester resin, bubble & smoke ^ dissolve and melt the plastic container that it is held in. Also noxious fumes will emanate into the air.
b) Epoxy resin, depending on the type (as there are as we know several types of Epoxy for various applications) tends to do the same as above but can become slightly more toxic if it reaches this stage SO DO BE WARNED
If your mixture is correct though, and you have mixed it in small quantities and spread it over the area thinly - one should have no problem with heat generation.
The things to be cautious about are - the materials which are being bonded together - glass fibre and wood - one will generally have no problems bonding with the polyester/epoxy based resins. Time to worry is when you have certain plastic hulls and oily timbers such as teak/Iroko which we have to use special glues/treatments for bonding.
John
ps remember heat + smoke make man take action and run fast :-)
Heat is ALWAYS generated during the curing process especially with poly resins its a chemical reaction so you are mistaken and your are seriously misinforming the guy and i suggest you research what your saying because you are WRONG .
However epoxy is fine for gluing in wooden parts into a grp hull and many plastic ones as epoxy doesnt generate near as much heat as polyester resin does so he should be fine. But to say the only time resin gives off heat is when the mix ratio is wrong is totally and utterly WRONG .
Instead of using epoxy try PU adhesives they bond well and remain semi flexable so will never come apart even if the hull flexes slightly ive even used it to bond high powered powerboat hull decks to the hull and its very strong .
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I recently tried Soudal Fix All high tack invisible adhesive. Amazing stuff, looks like clear silicon but much tougher, stays flexible, a bit strange to handle as it comes out of the cartridge very stiff, but spreads and works easily has good tack and is touch dry in an hour but cures in 24, very light and can fill large gaps without sagging, highly recommended.
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The quantity of Adhesive you will be mixing up in any period of fixing planks to balsa will not be thick enough to cause any heat problems and certainly no warping.
The testament to this is the laying up of GRP with resin. Larger amounts will be mixed for use, but it will be applied quickly with a large enough brush to get the resin on efficiently and in a thick enough layer to wet the glass matt/cloth and seal it in but not build up a surplus. Even the Gelcoat is only thick enough to do its job of providing a smooth layer, possibly with the fine detail.
With any glue, paint, filler etc, if you are unsure then test glue scraps of the material you plan to use together to see what happens. You would see very quickly that the layer you require will not be very thick, and will probably have ridges etc in it from the application, but even this will be squoze down as you clamp them reducing their capacity and risk of serious heat generation.
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Yes we are all looking forward to that! O0 :-))
On a serious note I have not tried it because of the nastiness of failure but how good are the "no nails" type products for modelling?
far better than the four types of Gorilla glue type rubbish I have used...
.wouldn't waste my money on any more of that brand of product.
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WELL!!!!
...I reckon RWH is now wishing he'd never asked the question, as there are now on the table, more solutions and does and don'ts than you can swing a cat at...
..
I just wonder whether we will ever reach a consensus on here that is actually helpful to a newcomer, {-) {-) %% %% {:-{ {:-{ :(( ok2 :-))
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Neil I am very surprised at what you have said about Gorrilla glue as Ive been using this for a couple of years....YES of course the Brown Gorilla glue is a right so and so as it expands but their Pva is darned good and also both the superglue's...once it's on it is on
Dave
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Me too been using Gorilla glue over the past few years- personal preference at the end of the day, experience doesn't always mean someones right, always worth trying different options.
Seasons best wishes to all past and present.
Rich
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I was introduced to Gorilla Glue Clear at a recent woodworking show and bought it to fix the outer wooden strakes of my Tug onto a Fibreglass Hull. It is brilliant when you follow the instructions. As a trial I glued 2 pieces of 4mm square aluminium about 1 cm long together and clamped them overnight. I cannot shift them now! Thoroughly recommended.
John
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Good Morning
I've been using this epoxy mix for a number of years and had good results with it. Another model builder had been using it and found it works well.
Not sure where you might find the product in the UK but sold over here in both hardware stores and the building material supply yards.
https://www.pcepoxy.com/products/permanent-repair/pc-11-paste-epoxy/
Comes in both the dispenser type tubes and also in small cups and you can mix it. Sands well after it has dried.
Merry Christmas!
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I use adhesives used in the building industry with good results. Some of the traditional glues we have used over the years have now been superseded by newer products on the market but you makes your choice. Never used Gorilla glue but I seems to have good feedback.
Stan
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Neil I am very surprised at what you have said about Gorrilla glue as Ive been using this for a couple of years....YES of course the Brown Gorilla glue is a right so and so as it expands but their Pva is darned good and also both the superglue's...once it's on it is on
Dave
sorry dave but just my opinion...
the brown bubbly stuff activated by moistire has never worked for me, even when clamping, and it takes longer to clean off excess than the gluing time...
.thus wasting twice the time...
.and TBH it doesn't resist knocks such as dropping your hull on the floor due to clumsiness.
the white pva I have found, although good sticking power takes too long to set compared with a good aliphatic.
the superglue sticks fingers instantly and not even my cyano release liquid will help, but once set is very brittleand the slitest knock just shatters the glue line and the thing glued falls apart.....
as for the duct tape......I have used numerous duct tapes that will adhere to my silicon moulds for casting fittings when I have got fittings too close to the edge of a mould, and the tape has always stuck to the silicon...
...gorilla duct tape just don't cut it...
..it sticks to itself admirably, to admirably that it leaves half its stickiness to the next layer down, but to timber and silicon and for any other target that I can think I have used it on...
.I get better sticking bower from a roll of cellotape
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i'll never buy the stuff again in any form.
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Just like speed controllers each one will have its good points and bad points. Sadly this applies to the glues we use. We could discuss for ever more we all have our own personal choice you pays your money and make your choice.
Stan.