Can I fiberglass over Helmsman Spar Urathane?

[WarPony]

I've been putting off skinning the roof of my TTT with aluminum for awhile. I got to thinking about using fiberglass cloth but have already put on the Spar urathane several months ago. Is it too late?

[BILLYL]

I would say no. There should be no problem. My suggestion would be to sand the surface with 120 grit paper - get a nice tooth on the finsih and go from there.

Keep us posted on your progress.

Bill

Also- where are you getting your supplies from?

[WarPony]

Bill, you stated there "should" be no problem......... I haven't ever used 'glassing in a large-scale project before. Done some small body patching on some cars but nothing that anybody will see. Might be more that I bargained for in the long run.

[DestinDave]

Jeff... don't know how epoxy would behave over spar urethane but I do know what happens over varnish. A few years ago I varnished all the exterior teak (13 coats with wet-sanding in between coats) on a yacht and then the owner had someone come in spray clear Imron (an epoxy paint). In the full sun the varnish wants to expand and under the hard Imron finish it wasn't able to. Result: The Imron cracked and crazed everywhere and the whole mess had to be sanded down and redone. Just guessing but I'd say the same could happen with urethanes/epoxies... Unless someone can say that they've done it and it's okay I'd be leary of trying it... Just my 2 pennies worth... Dave

[WarPony]

Thanks, Daver! That's all I need to know. I'll stick with the aluminum skin for the top.

[Chris C]

War Poney, talk with Doug.............he's a satchel full of knowledge when it comes to this subject.

[madjack]

...I would contact either RAKA or West systems...I beleive they are both listed in the supplier links above...that is if you don't get a definitive answer here
madjack

[doug hodder]

thanks Chris, I appreciate the compliment...but I certainly am not the "epoxy wizard" I can only go by my results and experience....Typically epoxy should be laid down on bare wood or dyed wood....additional layers do need a tooth to attach to....I agree with Madjack about checking with the manufacturers...I always think of it this way....always put your most durable material as the first coat...any other additional top coats can do their thing on top of this one...but if you try to lock in a material that needs to expand and contract with something that doesn't move as much, you are going to have problems...checking....I had a problem on my interior doors...shot them in urethane...ran out and tried to shoot lacquer over them....the finish was too "hot" chemically and caused the doors to wrinkle up...I've shot spar over lacquer but it doesn't work the other way....I'm willing to bet that the helmsman is going to want to move more than the epoxy....you can get them to bond...but I'll bet it isn't the optimum finish...When we talked before Jeff...I thought you were going to do something other than glass cloth....For cloth application, I can help you out and I'm sure Dave can also...largest I've done is 4x16 feet in cloth....hope I was able to help...Doug

[WarPony]

Doug, I have gone too far for 'glass on this project. I like the waterproof properties it has. I'll get some stuff and experiment this winter and probably use it on my next TTT.

[Juneaudave]

I'm thinking 4 oz glass/epoxy over the top of my soon to be started woody, with paint over the roof and clear coat to match my tow vehicle. Axle should be in next week. I don't think I would put glass/epoxy over varnish...based on my experience with strippers..the porosity of the wood with the first layer of epoxy helps "suck" the glass to the wood and create a really good bond. If the wood was sealed with varnish, I would be concerned with bonding and with the possibility of the glass "floating" if you were not really good squeeging the fabric.