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Re: XPS and Epoxy

PostPosted: Thu Jan 05, 2023 11:08 am
by kstills
Squigie wrote:.

PMF'd foamies, to me, are like the modern homes in areas with no building code, or limited building code, where all of the anti-racking comes from an off-brand Tyvek wrap and siding installed directly onto the exterior wall studs. Sure, it saved a little money. But at what cost in lifespan and future maintenance?


This might be a bit unfair, as from what I can see the durability of the builds isn't in question.

My primary desire to go the epoxy route is to get a smooth finish that will look good on the interior of the van. If the PMF method would get me there, I'd be doing that in a heartbeat. But from everything I've read here, including the Hotwire Foam Fusion thread, the only way I've seen to get the aesthetic look I desire (smooth, paintable finish) is going with epoxy and a glass mat.

Re: XPS and Epoxy

PostPosted: Thu Jan 05, 2023 11:20 am
by kstills
Squigie wrote:Aircraft and hobby aircraft (RC) builders have been doing this for years. More recently, it has become a more popular forming method for custom auto body panels, as well (but usually with an acetone rinse afterward, to remove the foam and leave just the shell if it is the final panel.



This just hit me.

Way cool, my mind is spinning thinking about the shapes that might be able to be formed using this method.

Just off the top of my head, I would suspect you could make some pretty lightweight doors using this method.

Re: XPS and Epoxy

PostPosted: Thu Jan 05, 2023 11:21 am
by kstills
Is it just me, or does the abbreviation for the website remind anyone else of Winnie the Pooh? :lol:

Re: XPS and Epoxy

PostPosted: Thu Jan 05, 2023 12:00 pm
by tony.latham
Just like with PMF you will have to incorporate something to hold fasteners. A strip of wood to hold hinges screws. If you have through fasteners, something like a dowel with a hole drilled through it so you can tighten a bolt without crushing the foam underneath.


Spot on.

And by the way, I really dislike using fiberglass matt. The stuff drives me crazy.



:thinking:

Tony

Re: XPS and Epoxy

PostPosted: Thu Jan 05, 2023 12:05 pm
by tony.latham
Best try this on scraps first ... :NC


Glen:

It ain't difficult, especially when using microspheres for a thickening agent to level in the low spots.

Image

That's with two sandings using a random orbital—thirty minutes for the first and maybe twenty for the second.

Tony

Re: XPS and Epoxy

PostPosted: Thu Jan 05, 2023 11:45 pm
by jakejakejake
There are a few of us around
171174
Ill be starting fairing and paint soon.

here's my build on the YT
https://www.youtube.com/@ThatJakeWorldWide/videos

here's some great reading material
http://www.captoscana.com/captoscana/Do ... uction.pdf

I would be happy to answer any specific questions that you have.

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 8:18 am
by kstills
Jake,

Thanks for the offer. I'm working my way through your videos atm, and I expect I'll be picking your brain in the upcoming days as my supplies arrive. Have you seen the Stone Coat guys videos? They do countertops and shower surrounds, so basically flat panels. Their last coat, which you couldn't do on a TC like you built, involves building a dam around the panel and flooding on the epoxy. That's kinda sorta how I envision my cabinet construction taking place.

Btw, love the dog, love the shop even more. To have that kind of space...... :shock:

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 9:55 am
by jakejakejake
kstills wrote:Have you seen the Stone Coat guys videos? They do countertops and shower surrounds, so basically flat panels. Their last coat, which you couldn't do on a TC like you built, involves building a dam around the panel and flooding on the epoxy.


Surfboard builders do a similar process too, sometimes referred to a hot coat or flood coat. It makes a lot of sense on a small(er) part, but over a large area you begin adding a lot of excess resin weight. Resin without glass reinforcement in it tends to be brittle and crack prone, and sands like concrete!

Like Tony said mixing a filler into your resin is easy and cheap, doubles the volume of your epoxy, and will keep the overall weight of the part down. Im using glass micro balloons, and man it sands better than some body fillers that I have used!

Read through the descriptions of fillers at https://www.uscomposites.com/fillers.html (no affiliation, but they have treated me right) it will help flesh out some of my ramblings.

I'll give the supervisor some pats for ya!

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 11:16 am
by kstills
jakejakejake wrote:
kstills wrote:Have you seen the Stone Coat guys videos? They do countertops and shower surrounds, so basically flat panels. Their last coat, which you couldn't do on a TC like you built, involves building a dam around the panel and flooding on the epoxy.


Surfboard builders do a similar process too, sometimes referred to a hot coat or flood coat. It makes a lot of sense on a small(er) part, but over a large area you begin adding a lot of excess resin weight. Resin without glass reinforcement in it tends to be brittle and crack prone, and sands like concrete!

Like Tony said mixing a filler into your resin is easy and cheap, doubles the volume of your epoxy, and will keep the overall weight of the part down. Im using glass micro balloons, and man it sands better than some body fillers that I have used!

Read through the descriptions of fillers at https://www.uscomposites.com/fillers.html (no affiliation, but they have treated me right) it will help flesh out some of my ramblings.

I'll give the supervisor some pats for ya!


The stone coat guys didn't sand for any reason aside from matting the finish a bit. Their finish, and the guy in the first video I posted, was smooth enough in the application I'm foreseeing that I would be happy as is. I can see that larger surfaces wouldn't be able to be kept as smooth because of the different shapes involved.

It's killing me having to wait to get my supplies, lol. I really want to see how this turns out.

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 11:26 am
by Squigie
Use epoxy, not resin.
Resin is so much more problematic and likely to degrade quicker. Not the least of its problems is the guarantee that you will become sensitized and have reactions with repeat exposure.

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 12:41 pm
by jakejakejake
Squigie wrote:Use epoxy, not resin.
Resin is so much more problematic and likely to degrade quicker. Not the least of its problems is the guarantee that you will become sensitized and have reactions with repeat exposure.



Note when I say resin I'm talking about epoxy. Resin is an all encompassing word that covers a ton of different materials. epoxy, polyester, vinylester etc are all "resins"

Sensitization is a concern with any of them, even epoxy. Wear your PPE when necessary and set your workspace up with some airflow and you will be fine.

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 12:43 pm
by jakejakejake
kstills wrote:It's killing me having to wait to get my supplies, lol. I really want to see how this turns out.


Im in the same boat! I was about 24oz of material short to finish some last minute details before paint. running out at the start of the Christmas holiday put me back a couple of weeks!

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 2:10 pm
by kstills
jakejakejake wrote:
kstills wrote:It's killing me having to wait to get my supplies, lol. I really want to see how this turns out.


Im in the same boat! I was about 24oz of material short to finish some last minute details before paint. running out at the start of the Christmas holiday put me back a couple of weeks!


Just heard back, all the raw materials should be here tomorrow! :twisted:

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 6:53 pm
by jakejakejake
kstills wrote:Just heard back, all the raw materials should be here tomorrow! :twisted:


Do you have gloves, mixing cups, mixing sticks, and chip brushes ready to go? I always seen to be short one of the four. I get everything at harbor freight besides the cups. I mostly use 6 or 12oz clear no name cups from the grocery store party aisle. Im looking forward to your build thread!

Re: XPS and Epoxy

PostPosted: Fri Jan 06, 2023 11:09 pm
by ghcoe
A good read about fiberglass, canvas, wood, TBII and paint. Have to read the whole article to get the full picture.

https://www.tonygrove.com/articles/nordic-folk-boat.php