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Author Topic: Springer Tug  (Read 4109 times)

lakeshore

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Springer Tug
« on: October 11, 2012, 12:31:21 PM »

Hi
Just about finished my first Springer Tug build and need to know the best way to waterproof the plywood hull.
I have used three coats of yacht varnish on the inside of the hull and wonder what to use on the outside to make it waterproof.  Do I use a combination of gloss paint and yacht varnish if so in what order would I apply them, or just use one of them.

Cheers
John.

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Neil

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Re: Springer Tug
« Reply #1 on: October 11, 2012, 12:39:41 PM »

polyester gelcoat and tissue would be the best way...........resin isn't waterproof.
neil
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Subculture

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Re: Springer Tug
« Reply #2 on: October 11, 2012, 06:14:36 PM »

It's waterproof enough. You could use epoxy resin and tissue for a really tough and watertight finish.

Neil

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Re: Springer Tug
« Reply #3 on: October 11, 2012, 10:02:46 PM »

It's waterproof enough.

that's why modern lifeboats put on a ton and a half in weight over their lifetime with the weight of water that seeps in through even the toughest of gelcoats................
if they were just resin'd they'd put on a hell of a lot more. %% %% %% %% %%
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Subculture

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Re: Springer Tug
« Reply #4 on: October 11, 2012, 10:17:34 PM »

If you look at the vast majority of model submarines, most of which free flood, you will find that the consturction often GRP, and the inside is usually plain resin and matt or cloth exposed to the water surface, and they have to deal with water pressure too. I've yet to see any adverse effects from this. Some used to apply a float coat to the inside, but it adds a lot of displacement, and is now generally considered to be unnecessary.

Full size boats tend to spend a lot more time in the water, so I would class them a little differently to a model which is likely to get dipped for a few hours each week at the most. I should add that applying gelcoat to hull is a bad idea unless you add a wax additive, because it is air inhibited and will remain tacky, and it's too thick to use for laminating with cloth or tissue anyway. If I use gelcoat, I brush it in on it's own, then apply tissue or cloth over the coating, once set using laminating resin.

CGAux26

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Re: Springer Tug
« Reply #5 on: October 11, 2012, 10:20:47 PM »

My Springer, now 4 years old, has the outside of the hull coated with 2 coats of West Marine epoxy.  No tissue, no FG cloth.  It has survived dozens of "Springer Toss" launchings and a few water polo games.  Tough little boat.   <*<Hope you enjoy yours.   :-))
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Tug Fanatic

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Re: Springer Tug
« Reply #6 on: October 12, 2012, 11:16:39 AM »

My models have always been based on fibreglass hulls so these are questions not answers. As a kid a very long time ago I remember my father building me a model boat from plywood that previously had been the back of a wardrobe so it wouldn't have been water resistant or anything. He was not a skilled modeller so I am sure that the joints were less than perfect but using ordinary varnish (& talcum powder to help gap filling) he made a serviceable model. So...................

Epoxy & Polyester resins are "modern" and "sexy" but are they necessary? Wood model boats (& sailing dingies etc) have existed for lot longer then either of them.

Do they really do a better job than the treaditional varnish (eg Ronsons Hardglaze) that can be purchased anywhere and perhaps used with a bit of filler (talcum powder) added for the second, or even the second & third coats? If you can sensibly use varnish can you skin with it using a tissue or thin fabric & does it improve dent resistance?

I know that polyester resins do not adhere to to wood as well as epoxies but given the way model boats are used are they in the real world any less good. Polyester resin can be purchased at Halfords etc very easily & for very little money. I suspect (???) that any water seepage through the resin would dry out in the centrally heated house where the model is likely to spend 98% of its life.

Is it possible to thin a normal epoxy - which I buy in 250ml bottles - to make it suitable for skinning thus avoiding the necessity of buying multiple adhesives? If so with what & in what ratio?

How much resin do you need to skin a Springer?

I ask these questions because glues can be such a large part of the cost of building a model - a West Epoxy kit might, for example, sound great but it isn't cheap for a model perfect for beginners, & often built by young persons. It is also easily possible to end up with a horrible mess if skinning goes wrong.
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CGAux26

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Re: Springer Tug
« Reply #7 on: October 17, 2012, 12:22:00 AM »

I think I remember mixing a total of about 1/4 to 1/2 cup of epoxy to put one coat on the outside of the hull of my Springer.  That's really stretching this old man's memory, of course.  Full strength West Systems epoxy, spread with a cheap foam brush (have extras ready-the epoxy attacks them).  WS advises not to thin it, as thinning makes the finished epoxy much weaker.  I use the slow hardener, and it gives an hour or more open time in a cool shop.  It is so slow that it will level itself to a glassy finish.  And keep the surfaces as flat and level as possible because the epoxy will run on vertical surfaces.

As to the cost of WS versus cheaper polyester or other stuff, "The good feeling from buying at a cheap price vanishes quickly in the face of poor quality."  Or you get what you pay for.   O0
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Tug Fanatic

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Re: Springer Tug
« Reply #8 on: October 17, 2012, 10:49:17 AM »


...........As to the cost of WS versus cheaper polyester or other stuff, "The good feeling from buying at a cheap price vanishes quickly in the face of poor quality."  Or you get what you pay for.   O0

Agree totally. Just wanted to remind those with a very limited budget that there are more affordable alternatives. Keeping the cost down hopefully encourages more to build a model.
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Subculture

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Re: Springer Tug
« Reply #9 on: October 17, 2012, 01:45:56 PM »

If you go to somewhere like Halfords for polyester resin, you'll pay near enough as much for that as you will for epoxy resin from online sellers.

I work with both resins, they each have their pros and cons. Epoxy is certainly a lot less pungeant, but you need to be accurate with the mixing ratios, and you need a warm place, or a hot box to get it to cure well overnight.

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Re: Springer Tug
« Reply #10 on: October 18, 2012, 10:59:31 AM »

I know that epoxy is the best but unless you know of a better supplier ( I would be very interested to know who) it is much more expensive.

Checking ebay a West 500ml kit is about 24 delivered as is 1litre of "other" epoxy. 250ml epoxy from my local model shop is about 14. 250ml polyester (which I guess is more than enough for a Springer) from your local Halfords is 3.99. If we could use something that we could "reclaim" from the shelves in our garage/shed then the beginners investment would be even less.

The best way to use these "free"/low cost alternatives would, I thought, be a worthwhile discussion.

Using West epoxy the hull coating might well be the most expensive bit in the model.

As I said I know that epoxy is best but a discussion of the cheaper alternatives might encourage some to have a go who might otherwise not. We don't only discuss the most expensive motors, receivers, servos etc even though you get what you pay for in those as well. 

End of soap box.   :-X
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Re: Springer Tug
« Reply #11 on: October 18, 2012, 12:36:48 PM »

I haven't used west systems, although it has a very good reputation amongst those who do use it, the 1:1 mixing ratio makes life easy. I use reactive resins epoxy. This has a 2:1 mixing ratio, which is easy enough if you have some accurate scales to weigh it out. Very nice resin, they do a nice filler too, which spreads like polyester filler. A 1.5kg pack is about 25 with the dreaded VAT, so that balances up fairly well with the 4 per 250ml cost of polyester resin from Halfords. The downside is you can't purchase very small quantities, but if you're part of a group, you may be able to spread the cost out amongst a few modellers, or use the resin for other models- I find epoxy has a good shelf life.

http://www.resinstore.com/epoxy-packs.html

CGAux26

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Re: Springer Tug
« Reply #12 on: October 18, 2012, 10:48:07 PM »

Actually, West Systems is mixed at 5 parts resin and 1 part hardener.  It's sold in cans at those proportions, so I buy a quart of resin and a can of hardener in a can about the size of a cup.  I also invested in their metering pumps.  Screw one on each can, resin and hardener, and they measure out just the right amount. 1 squirt of resin and one squirt of hardener, gives the 5:1 ratio.  No weighing, no measuring cups, little mess.  I leave the pumps on the cans, too.  I had a can of the fast hardener for over 2 years, and it turned brownish red, but still did the job.
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Re: Springer Tug
« Reply #13 on: October 19, 2012, 11:35:55 AM »

Ah, I see. So it's the pumps that provide the 1:1 mixing ratio. Fair enough, no advantage then for manual mixing, in fact the Reactive resin is easier to calculate at 2:1.
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