How Much Resin?

Stemar

Stemar

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I'm building a doghouse for Jazzcat. It's ply to be covered in glass fibre cloth and a scrim, both left over from a previous project. The total surface area (inside and out) is around seven sq metres. Can anyone tell me how much epoxy resin I'll need, please?

Once it's done, it'll be finished a few coats of paint. I'm tempted to go for two pack as I hope it'll resist the depradatoins of shitehawks better. Is that correct, or would one pack be easier and just as effective?

Thanks in advance

Supplementary question: It gets a bit cold overnight, 6-7 deg, at the moment. Does that mean the slow hardener I've used today will just take longer to cure, wait until it gets warm tomorrow to cure or be screwed and never go off properly?
 
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Depends on the weight of the cloth being used. Broadly speaking 100gsm cloth takes 100g of epoxy. But I find you usually end up needing 20% or so extra epoxy.
 
Also you’ll need extra to prime the bare wood. So if using 100gsm for 7sqm; it will be 7 x 100gm = 700gm plus extra for priming. I’d probably mix at least 1200 gm. You might have some left over but better that than to be short.
 
If you are using epoxy the low temperature shouldn't be a problem, assuming that you are doing this in a garage / shed. When it gets cold epoxy stops curing and restarts once it warms up.

I did my bow thruster on my last boat over winter weekends years ago with no problems.
 
Why use epoxy? Ordinary resin will work just as well for this project. Instead of painting it, why not coat it with flow coat. Provided the glassfibre surface is smooth, this should allow you to sand and compound the flow coat to a permanent shiny surface that would look professional. This should also work out a lot cheaper than epoxy and paint.
 
The concept of using GRP to cover plywood is not as good as it might seem. Much depends on the thickness of GRP. Is it plywood with thin coating of GRP or is it thick GRP on a plywood mold. The former might be inclined to delaminate from plywood. Especially polyester resin which will not stick as well as epoxy. The latter concept would be fine in polyester. I would go thin ply thick GRP but maybe you are committed to thick ply. Such that 2 pack paint may be just as good as GRP.
As said warm up the ply before applying resin as this will tend to draw resin in to the wood. Then add the glass.
As for resistance to bird droppings I think it all depends on the surface finish. Sand it smooth then more resin with pigment or 2 pack paint. ol'will
 
Stemar said:
I'm building a doghouse for Jazzcat. It's ply to be covered in glass fibre cloth and a scrim, both left over from a previous project. The total surface area (inside and out) is around seven sq metres. Can anyone tell me how much epoxy resin I'll need, please?

Once it's done, it'll be finished a few coats of paint. I'm tempted to go for two pack as I hope it'll resist the depradatoins of shitehawks better. Is that correct, or would one pack be easier and just as effective?

Thanks in advance

Supplementary question: It gets a bit cold overnight, 6-7 deg, at the moment. Does that mean the slow hardener I've used today will just take longer to cure, wait until it gets warm tomorrow to cure or be screwed and never go off properly?
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I defo would not waste my west epoxy on a dog kennel. I hope its the cheaper polyester type resin.
 
Thanks, everybody.

Well, the resin I used to glue reinforcement to the top yesterday has gone off with no problems, even though it was in the open, under a carport-like structure, proving Boathook's point.

As for using Epoxy rather than polyester, it's mainly because I've used epoxy for several small projects, so I'm familiar with it. I've got to get more epoxy anyway, as I have one more piece of reinforcing to fit before I cover everything. The sides, which will carry the load and, actually be mostly window are 9mm ply, though I think I'm going to double it on the part that will carry the most loading, while the roof is 6mm, with a few 6mm reinforcements. If I was any good at CAD, I'd have a design I could post, but the plan is mostly in my head.
 
Stemar said:
Thanks, everybody.

Well, the resin I used to glue reinforcement to the top yesterday has gone off with no problems, even though it was in the open, under a carport-like structure, proving Boathook's point.

As for using Epoxy rather than polyester, it's mainly because I've used epoxy for several small projects, so I'm familiar with it. I've got to get more epoxy anyway, as I have one more piece of reinforcing to fit before I cover everything. The sides, which will carry the load and, actually be mostly window are 9mm ply, though I think I'm going to double it on the part that will carry the most loading, while the roof is 6mm, with a few 6mm reinforcements. If I was any good at CAD, I'd have a design I could post, but the plan is mostly in my head.
Click to expand...
You could post a few photos to show your progress. It may even encourage a few others to follow your example.
 
I have heard it suggested that using initial coat (s?) of uncatalysed resin aids penetration and adhesion. I THINK the idea is that catalyst slowly penetrates from later coats so it goes off eventually but stays liquid longer to better penetrate the wood.

I dumno if this is true
 
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