Glassing Advise
11-13-2002, 02:30 PM
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Glassing Advise
I have recently finished building a .60 size float system for my ¼ Scale J3 Piper Cub. Now I would like to glass the floats, as I think it will give me a good opportunity to practice glassing before I begin my next project, a Ziroli P40D Razorback. There appears to be many options regarding glassing techniques and materials. I was hoping someone might have some suggestions regarding both of the aforementioned points, as well as some helpful books too.
Thanks,
Jed
Thanks,
Jed
11-13-2002, 03:57 PM
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Glassing Advise
Keep them very light. I would use the lightest cloth you can find. One method I have seen on floats that works is 1 layer of very light, 1/2 oz cloth and 30 min epoxy thinned with alcohol. Might use 2 layers on some of the stress joints. After they are glassed, paint on Red devil spackle compound thinned with water. This is very light too. Then you can sand to a really smooth finish and the spackle will fill the holes in the glass. Then prime and paint. I have done this on planes and it works great.
11-13-2002, 08:06 PM
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Glassing Advise
Jed,
I used to use epoxy for glassing but I have moved EXCLUSIVELY to a water based polyurethane product called PolyCrylic by MinWax. You can purchase it at any home improvement store at roughly $9.00 a quart.
There are several reasons I moved to it:
1. Easy to apply! Just lay the cloth down and use a one inch brush to apply the polyCrylic to the glass.
2. NO SMELL OR FUMES!!!!!!
Unlike epoxy or Polyester resin this does not smell bad or give off dangerous fumes.
3. LIGHT, LIGHT, LIGHT!
Since it is water based most of it evaporates. The manufacturer claims that 80% of the product is water and all of that evaporates. I also employ another technique to make it even lighter... read on...
So, now that you know why I use it here is how I do it.
1. Prepare the surface well.
I usually sand down to like a 300 grit sandpaper to prepare the surface. Remember, this is a thinner substance than epoxy or polyester resin so you should not count on it to smooth out ding and such.
2. Lay your glass cloth over the section to be covered. Think about how you want things to overlap. If you where doing a wing for instance, you would generally glass the bottom then the top of the wing. Don't worry to much about the seams. They will smooth themselves out when you apply the other side.
3. Apply a thin coat of PolyCrylic over the glass, you want to apply just enough to make the glass stick to the wood. Let that coat dry (about two hours).
4. Apply a second thin coat just to make sure the cloth is stuck to the wood well. Let it dry (about two hours)
5. The most important step!
Mix three parts PolyCrylic with one part Microbaloons and apply a good coat of that to the surface. This coat will fill the weave in the cloth and smooth it out. Let that coat dry at least two hours.
6. apply one final thin coat of the PolyCrylic on the surface and then let the entire side dry for at least 24 hours. Then go back trim the edges of the glass cloth and I do a light sanding with 330 grit paper just to knock off any dust or sawdust that might have floated into the finish.
That's it! Now just pick your favorite primer and start your paint job. I have found this method to be much easier to manage than epoxy or polyester resin.
Good luck!
I used to use epoxy for glassing but I have moved EXCLUSIVELY to a water based polyurethane product called PolyCrylic by MinWax. You can purchase it at any home improvement store at roughly $9.00 a quart.
There are several reasons I moved to it:
1. Easy to apply! Just lay the cloth down and use a one inch brush to apply the polyCrylic to the glass.
2. NO SMELL OR FUMES!!!!!!
Unlike epoxy or Polyester resin this does not smell bad or give off dangerous fumes.
3. LIGHT, LIGHT, LIGHT!
Since it is water based most of it evaporates. The manufacturer claims that 80% of the product is water and all of that evaporates. I also employ another technique to make it even lighter... read on...
So, now that you know why I use it here is how I do it.
1. Prepare the surface well.
I usually sand down to like a 300 grit sandpaper to prepare the surface. Remember, this is a thinner substance than epoxy or polyester resin so you should not count on it to smooth out ding and such.
2. Lay your glass cloth over the section to be covered. Think about how you want things to overlap. If you where doing a wing for instance, you would generally glass the bottom then the top of the wing. Don't worry to much about the seams. They will smooth themselves out when you apply the other side.
3. Apply a thin coat of PolyCrylic over the glass, you want to apply just enough to make the glass stick to the wood. Let that coat dry (about two hours).
4. Apply a second thin coat just to make sure the cloth is stuck to the wood well. Let it dry (about two hours)
5. The most important step!
Mix three parts PolyCrylic with one part Microbaloons and apply a good coat of that to the surface. This coat will fill the weave in the cloth and smooth it out. Let that coat dry at least two hours.
6. apply one final thin coat of the PolyCrylic on the surface and then let the entire side dry for at least 24 hours. Then go back trim the edges of the glass cloth and I do a light sanding with 330 grit paper just to knock off any dust or sawdust that might have floated into the finish.
That's it! Now just pick your favorite primer and start your paint job. I have found this method to be much easier to manage than epoxy or polyester resin.
Good luck!
11-13-2002, 11:21 PM
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Glassing Advise
Mike,
Any issues with the PU lifting off the a surface after it's cured?
There was alot of "buzz" about using PU for fiberglassing a couple of years ago. Last I heard, the converts were back to epoxy because of bad experiences with the PU lifting off the wood too easily.
What's been your experience?
Any issues with the PU lifting off the a surface after it's cured?
There was alot of "buzz" about using PU for fiberglassing a couple of years ago. Last I heard, the converts were back to epoxy because of bad experiences with the PU lifting off the wood too easily.
What's been your experience?
11-13-2002, 11:55 PM
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Glassing Advise
I have never had a problem with that occuring. I would guess though that the heavier the glass cloth, the more coats you need to add because of the THIN layers of PU. Also I have discoverd NOT to use a sanding sealer. It will pull up if you have used a sealer. That may be the reason it would peel up after a while. If you feel you must seal the wood just brush a thin coat of PolyCrylic on the wood BEFORE you add the glass cloth and after it dries hit it with some 300+ grit sandpaper.
I know that the PolyCrylic leaves a +-5 micron thick coat of a blender layer on the top of each coat that allows a new coat of it to bond to the previous layer. That's another reason to sand the final coat to remove that.
I've done three planes with it and have not had a problem yet!
My 2 cents! :-)
I know that the PolyCrylic leaves a +-5 micron thick coat of a blender layer on the top of each coat that allows a new coat of it to bond to the previous layer. That's another reason to sand the final coat to remove that.
I've done three planes with it and have not had a problem yet!
My 2 cents! :-)
11-14-2002, 01:36 PM
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Thanks Guys
The information is exactly what I was looking for...thanks! Art, your website is extremely informative, and worthwhile for anyone else interested in glassing to stop by and check out. Also, Mike I found your advice extremely informative and easy to understand thanks!
Without pushing my luck...any thoughts on finishing the glassed floats e.g., priming, panel lines, and rivets?
Jed
Without pushing my luck...any thoughts on finishing the glassed floats e.g., priming, panel lines, and rivets?
Jed
11-14-2002, 01:56 PM
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Glassing Advise
Jed,
Here is my 2 cents on those items.
As far a primer & paint.... I have used two different kinds and they both work well. The number 1 item you should be concerned with is having a GOOD compressor & auto finishing gun. I have used Perfect paint & primer and have also used standard auto paint & primer. The perfect paint is alot easier but make sure it's not old or you will not be pleased with the results. I got an old can from Tower and it was all clumpy. THey took it back and sent a new one and I have never had that problem since.
I use drafters tape 1/64 wide. I prime, fix any problems, prime again, then lay the tape out where the panel lines are. Then I spray one thin coat of silver. Let it dry. remove the tape and then spray a VERY thin coat of silver again. Now you have a good base that is very scale like. Your base is silver so if the paint you cover the silver with chips off you have a very scale look and there is recessed panel lines. As far a rivets check these guys out... http://www.acp-web.net/rcsp They have a rivet tape and they actually sell a kit with plenty of tape and a dispenser bottle. You do this step after you paint the silver on.
Just remember when you paint over the silver with your color of choice use thin coats so you won't fill up the panel lines and hides the rivets.
Good Luck!
Here is my 2 cents on those items.
As far a primer & paint.... I have used two different kinds and they both work well. The number 1 item you should be concerned with is having a GOOD compressor & auto finishing gun. I have used Perfect paint & primer and have also used standard auto paint & primer. The perfect paint is alot easier but make sure it's not old or you will not be pleased with the results. I got an old can from Tower and it was all clumpy. THey took it back and sent a new one and I have never had that problem since.
I use drafters tape 1/64 wide. I prime, fix any problems, prime again, then lay the tape out where the panel lines are. Then I spray one thin coat of silver. Let it dry. remove the tape and then spray a VERY thin coat of silver again. Now you have a good base that is very scale like. Your base is silver so if the paint you cover the silver with chips off you have a very scale look and there is recessed panel lines. As far a rivets check these guys out... http://www.acp-web.net/rcsp They have a rivet tape and they actually sell a kit with plenty of tape and a dispenser bottle. You do this step after you paint the silver on.
Just remember when you paint over the silver with your color of choice use thin coats so you won't fill up the panel lines and hides the rivets.
Good Luck!
