Finishing Epoxy

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Sure. Easy to use and sand. Not the best choice for laminating though as it is fairly thick.
 
I installed the tail cone on my Jayhawk and when I wiped the excess off around the seam where it contacts the aft end of the body I have about 1/4" wide band of epoxy very thin and level. I figure I would leave it there to help seal the seam and the go over it with spot putty glaze and sand it. If it doesn't work I was considering using the finishing epoxy on the tail cone and sanding it smooth
 
If you have it already for other purposes, West System 105/205 is a high quality alternative that is also very nice for finishing nose cones. It sands very well after several hours. Depending on the application I'll use it either with or without a layer of thin glass cloth (0.5 to 2 oz). It really makes a balsa cone/transition a lot tougher. Even worked for resining the foam on an Estes MIRV. The Aeropoxy laminating resin also fills the bill.
 
I've been using the BSI 20 Min Finish Cure for a couple months now. I really like it.
I've mostly used it for doing lightweight FG Cloth layups, on BT-80, 60, and LOC 1.14, aswell as Glassing Fins.
I have also used it the way Sodmiester does, to harden Cardstock Parts like Tail Cones and Paper Hat Tips, and one Transition.
It sands down very nicely.
I mix it in the tiny plastic shot glasses that you get at the Dollar Store, for $1 for 24.
I once tried just eyeballing it when mixing up a batch in a different vessel, and I got the Ratio wrong, and it never dried, so now I make sure that I mix it precisely by volume.
I understand that there are better Epoxies out there for my uses, but I'm not using large quantities, and until I do, won't need quarts or gallons.
 
I've been using the BSI 20 Min Finish Cure for a couple months now. I really like it.
I've mostly used it for doing lightweight FG Cloth layups, on BT-80, 60, and LOC 1.14, aswell as Glassing Fins.
I have also used it the way Sodmiester does, to harden Cardstock Parts like Tail Cones and Paper Hat Tips, and one Transition.
It sands down very nicely.
I mix it in the tiny plastic shot glasses that you get at the Dollar Store, for $1 for 24.
I once tried just eyeballing it when mixing up a batch in a different vessel, and I got the Ratio wrong, and it never dried, so now I make sure that I mix it precisely by volume.
I understand that there are better Epoxies out there for my uses, but I'm not using large quantities, and until I do, won't need quarts or gallons.

Do you just brush it on with epoxy brushes and let it dry? Does it leave brush marks. I use thin CA to strengthen balsa parts such as nose cones and tail cones and I already used thin CA on this tail cone, but since it might take a couple bad hits since its a tail cone just want to make sure I do everything to protect it.
 
Do you just brush it on with epoxy brushes and let it dry? Does it leave brush marks. I use thin CA to strengthen balsa parts such as nose cones and tail cones and I already used thin CA on this tail cone, but since it might take a couple bad hits since its a tail cone just want to make sure I do everything to protect it.

I've used it on Paper parts that have already been CA soaked, and on some that have not. I can't say there is much of a difference in the end strength wise, but the epoxy is much easier to sand smooth.
As to the brushes, I use the cheapest paint brushes they sell in Bulk at the Hardware Store. The ones that have all different color Handles and are only about 3/16" wide with the black plastic bristles. They're like $0.40 apiece.
I once tried using Foam Brushes, but the foam soaked up all the epoxy, and would not apply it to the work.
With the black plastic Bristles, the only time I've had an issue is with a bristle or two falling out, and then needing to pick it off of the work.
For spreading the 20 Minute stuff evenly into a Paper Part, I simply use my finger, while wearing my Nitrile Gloves. That definitely won't leave any brush stroke marks, but I have found the Epoxy to be thin enough that you generally don'y get them anyhow with a brush. It sands easily anyway if you did.
Now that I've been using it for awhile, I have a good feel for it, and get what by my standards are great results.
I'de recommend trying it without hesitation. I'm glad I did.
 
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I've used it on Paper parts that have already been CA soaked, and on some that have not. I can't say there is much of a difference in the end strength wise, but the epoxy is much easier to sand smooth.
As to the brushes, I use the cheapest paint brushes they sell in Bulk at the Hardware Store. The ones that have all different color Handles and are only about 3/16" wide witht the black plastic bristles. They're like $0.40 apiece.
I once tried using Foam Brushes, but the foam soaked up all the epoxy, and would not apply it to the work.
With the black plastic Bristles, the only time I've had an issue is with a bristle or two falling out, and then needing to pick it off of the work.
For spreading the 20 Minute stuff evenly into a Paper Part, I simply use my finger, while wearing my Nitrile Gloves. That definitely won't leave any brush stroke marks, but I have found the Epoxy to be thin enough that you generally don'y get them anyhow with a brush. It sands easily anyway if you did.
Now that I've been using it for awhile, I have a good feel for it, and get what by my standards are great results.
I'de recommend trying it without hesitation. I'm glad I did.

I just order some....looking forward to trying it out. Hobbylinc is slow with their shipping. Standard shipping now is like two weeks? Won't get here until the 10th or 12th
 
I tried it once..... Never again!
You are better off with either West Systems or Aeropoxy laminating resin kits.
US Composites has their own as well.

I like Bob Smith's 30 min for most of my builds but, never again for the their finish cure junk!
It takes 2+ hrs to set up

JD

Have any of you used this? I want to use it on a balsa nose cone and was wondering how easy is it to sand?

https://www.hobbylinc.com/htm/hlc/hlc209.htm
 
I tried it once..... Never again!
You are better off with either West Systems or Aeropoxy laminating resin kits.
US Composites has their own as well.

I like Bob Smith's 30 min for most of my builds but, never again for the their finish cure junk!
It takes 2+ hrs to set up

JD

I find it takes even longer than that, because my house is usually cold, but I'm not in any hurry, and I like the long working time when I'm doing something like the Glass Cloth.


What's the smallest Quantity of West Systems or Aeropoxy that you can get? Can you get 4oz. Bottles???
 
West Systems smallest size is a quart of the resin and a pint of the hardener. The measured pumps are a great addition to the WS product line and many people use their products just for this reason alone.
 
I used the heck out of BSI 20 Minute today! I found a new way to mix it too!
I measured it and combined the two parts, then stuck a small brush in my Dremel Clone and spun it to mix it at the lowest speed. Way better than stirring it with a Bamboo Skewer, and it set up a lot faster too.
I did layups, and glazed a plastic cone with it.
Once again I am satisfied with the results, and even more so now that I've found a way to mix it to perfection.

Talos and 104Cone 003.jpg

Talos and 104Cone 005.jpg
 
West Systems smallest size is a quart of the resin and a pint of the hardener. The measured pumps are a great addition to the WS product line and many people use their products just for this reason alone.


How much does that cost???
 
I've been using the BSI 20min Finishing epoxy for over a decade. No problems what-so-ever! Easy to mix 1:1 ratio. Is it more costly than other brands.. it is... but comes in nice smaller quantities. Unless you are dong huge layups or glassing big tubes, you don't need big volumes of epoxy! I have some U.S. Composites 3:1 Its nice.. but I cant say I like it any better or that it does anything I need more than the BSI does.


Jerome
 
So, after Shipping I'de be into it for $66.
I could buy a lot of building supplies for that much. Looks like West Systems is way too rich for my blood.

I'll Pass.

WestSystems 001.jpg
 
Just to put some numbers on epoxy costs.

Bob Smith Industries - most varieties are $12-13 for 9 oz (Google shopping results) = $1.33 to $1.44 / oz
Aeropoxy PR2032 quart kit (Aeropoxy store site)- $40.85 for 31 oz = $1.32/oz
West 105/205 quart resin + 8oz hardener (on US Composites site store): $47.00 for 40 oz = $1.17 / oz
US Composites 635 thin system 16oz resin + 5.3 oz medium 3:1 hardener kit: $15.75 for 21.3 oz = $0.74 / oz
US Composites 635 thin system 32oz resin + 10.6 oz medium 3:1 hardener kit: $23.95 for 42.6 oz = $0.56 / oz

So (ignoring shipping and tax) on a volume basis the BSI is the most expensive, but only by a little bit. It has the advantage of being available over-the-counter in hobby shops. West System epoxies can usually be bought OTC in marine stores, but often cost more than listed above when obtained that way. The US Composites is *considerably* less costly, and can be bought in a smaller package too. The Aeropoxy, West, and USC systems can all support different cure times via different hardeners for the same resin. There are significant differences among these in working properties and strength. Short cure times give lower strength and gumminess that inhibits sanding. There are some threads here with great info on tech data and testing of various epoxies...ultimately you have to decide what works for your uses and budget.

:grin:
 
Just to put some numbers on epoxy costs.

Bob Smith Industries - most varieties are $12-13 for 9 oz (Google shopping results) = $1.33 to $1.44 / oz
Aeropoxy PR2032 quart kit (Aeropoxy store site)- $40.85 for 31 oz = $1.32/oz
West 105/205 quart resin + 8oz hardener (on US Composites site store): $47.00 for 40 oz = $1.17 / oz
US Composites 635 thin system 16oz resin + 5.3 oz medium 3:1 hardener kit: $15.75 for 21.3 oz = $0.74 / oz
US Composites 635 thin system 32oz resin + 10.6 oz medium 3:1 hardener kit: $23.95 for 42.6 oz = $0.56 / oz

So (ignoring shipping and tax) on a volume basis the BSI is the most expensive, but only by a little bit. It has the advantage of being available over-the-counter in hobby shops. West System epoxies can usually be bought OTC in marine stores, but often cost more than listed above when obtained that way. The US Composites is *considerably* less costly, and can be bought in a smaller package too. The Aeropoxy, West, and USC systems can all support different cure times via different hardeners for the same resin. There are significant differences among these in working properties and strength. Short cure times give lower strength and gumminess that inhibits sanding. There are some threads here with great info on tech data and testing of various epoxies...ultimately you have to decide what works for your uses and budget.

:grin:

I kinda' figured it might break down something like that.
I can only afford to spend maybe $50 a month on Rocket Stuff, $80 if I'm lucky/non-scrupulous, so if I was to get the larger quantity stuff, it would be a Month without stuff to use it on.
I still need to find a month where I can get a new NAR Membership.
I'm sure I'll eventually want to try the West Systems, but right now it just makes sense to use the BSI from either my Local Hobby Shop of Amazon.
 
For small quantities and for what you're doing, hobby shop/BSI finishing epoxy will work just fine.

The advantage of West Systems is that it's used in the boating industry and you can buy the stuff over the counter in most locations where there is boating. It's not cheap, tho.
 
sitting here waiting for family to arrive.... Merry Christmas everyone!

Anyway, the epoxies that tend to have a 1:1 mixing ratio usually have a lot of fillers added in order to achieve that ratio. So those epoxies are likely to be less 'expensive' when you consider that a lot of what is in the container is not the actual binders themselves. That's why epoxies like WS have odd mixing ratios because they're much closer to the organic ratios that are required. More expensive- but more potent.
 
Amazon has the West Sytems stuff for $30 for the Quart of Resin and $20 for the 1/2 Pint of Slow Hardener. Free Shipping. Hmmm...
That's more like it.:)
 
While I buy US Composites by the gallon, I still use the hobby stuff for small jobs. Works well when I just don't want to mix up a bunch of resin. I just need to remember it is a small batch of the industrial stuff. It take hours to cure.
 
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