Crimea_River
Marshal
Anyone tried making thier own resin parts?
Tips, links welcome.
Tips, links welcome.
Home Made Resin Parts
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B-17engineer
Colonel
Best tip I can give you is when you cast the parts, if the mold is small enough, place it quickly in a can securely tied to some cord and wizz that sucker around over your head and use centrifical force to get the air bubbles out and get the resin in all the nooks and crannies in the mold. Becareful to make the sides of your mold thick enough so that it will not deform under the G's.
Good luck and remember that this can be done on the cheap!
Good luck and remember that this can be done on the cheap!
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- #4
Crimea_River
Marshal
Thanks Harrison. Sounds a bit complicated and pricey in that link.
Vick, I'm intrigued but I've never done this before. How do you do it "on the cheap"? What materials do you use and where do you get them? Harrison's link is a German guy and the stuff he uses doesn't sound like it would be availble here.
Vick, I'm intrigued but I've never done this before. How do you do it "on the cheap"? What materials do you use and where do you get them? Harrison's link is a German guy and the stuff he uses doesn't sound like it would be availble here.
Airframes
Benevolens Magister
Andy, most art and craft supply stores will stock Casting Resin and Hardener, also some model shops. moulds can be made either from polyurethane, from the same sources, or, for some small parts, from 'Plasticine' (kiddies play clay).
Basically, you'll need a 'master' from which to make the mould, and this can be, for example, a kit part, such as a wheel.
It's a long time since I made a 'full' mould with the polyurethane, and then only for relatively large parts, as the mould will need to be cut in half to allow extraction of the finished part, or made in such a way it can be 'peeled' back, like casting plater of Paris ornaments.
When using Plasticine for makine, say, a wheel, the 'master' can be pressed into the clay, and very carefully removed, and then repeated for the reverse side. (casting in two halves).
Resin is poured in, with the hardener added per the instructions, and allowed to set. Air bubbles can be a problem but, on small parts, if poured carefully and slowly, after thorough mixing, it shouldn't be a major problem.
Overall though, the materials are fairly expensive, even though the cost has decreased over recent years, so depending what it is you wish to mould, it's often cheaper to buy ready-made parts if available.
Hope this helps a bit.
Basically, you'll need a 'master' from which to make the mould, and this can be, for example, a kit part, such as a wheel.
It's a long time since I made a 'full' mould with the polyurethane, and then only for relatively large parts, as the mould will need to be cut in half to allow extraction of the finished part, or made in such a way it can be 'peeled' back, like casting plater of Paris ornaments.
When using Plasticine for makine, say, a wheel, the 'master' can be pressed into the clay, and very carefully removed, and then repeated for the reverse side. (casting in two halves).
Resin is poured in, with the hardener added per the instructions, and allowed to set. Air bubbles can be a problem but, on small parts, if poured carefully and slowly, after thorough mixing, it shouldn't be a major problem.
Overall though, the materials are fairly expensive, even though the cost has decreased over recent years, so depending what it is you wish to mould, it's often cheaper to buy ready-made parts if available.
Hope this helps a bit.
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- #6
Crimea_River
Marshal
It does Terry, thanks. My need is for the wing tanks on my CF-5, the 'peanut tanks'. The master will likely be a shaped wooden dowel, with a sealer applied. I like the idea of pouring two halves for this and gluing them together after the resin has set. I'll hunt around for the mold and resin compounds at some local stores.
N4521U
Colonel
Yep, I have, and I do! Did them for my Spit Mk.22 and P-51D Merlin's Magic. See attached.
N4521U
Colonel
Yep, I have, and I do. See attached for my Mk.22 and P-51D Merlin's Magic. It's actually pretty easy to do. Just have to make the mold box as small as possible, and to hold the part as stable as possible. Sometimes in the far recesses of the mold when pouring the resin in you get small bubbles, but them another part can be cast pretty quickly.
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Crimea_River
Marshal
Thanks. So what did you use for molds and resin and where did you get them? What I don't get is did you plunge the whole master into the wet mold, let it dry, then get it out or are there 2 halves to the mold. Is the mold material flexible or hard? Can't tell from your shots.
vikingBerserker
Lieutenant General
Very nice, this has some endless potential.
N4521U
Colonel
To show you how I set them up. Support the piece rigidly. I made the little box for the aileron from scraps of a kit box, taping all around. I supported the trailing edge of the wing from a sharpening stone, any heavy object will do. Then poured the mold material Slowly around it. The tail wheel is a bottle cap. I just wanted to make the wheel in two halves that I could file down to the width I want for a Single wheel, I abandoned this anyway. I just floated the wheel assy on top.
It is important, since we are not likely to be using a vacuum chamber to remove air bubbles, to mix the mold material SLOWLY! so as not to introduce air which will become the dreaded bends, Bubbles! This applies to the resin as well. But when you f*** up one, you can make another.
The mold will set up in about 25 minutes is all. The piece will pull free easily. Then pour in the resin mix, Slowly as well so as not to get voids in the bottom of the mold. When it sets up remove the piece, maybe pulling the mold away from the casting, tease it a little it comes free easily.
Any questions? Please ask.
If you want to make a two piece mold just stick a couple of pieces of sprue into the bottom mold, a few mm's sticking out as a register for the top half. Pour the top half over the piece with another piece of sprue attached to the part for a pouring tube.
Easy peasy!
It is important, since we are not likely to be using a vacuum chamber to remove air bubbles, to mix the mold material SLOWLY! so as not to introduce air which will become the dreaded bends, Bubbles! This applies to the resin as well. But when you f*** up one, you can make another.
The mold will set up in about 25 minutes is all. The piece will pull free easily. Then pour in the resin mix, Slowly as well so as not to get voids in the bottom of the mold. When it sets up remove the piece, maybe pulling the mold away from the casting, tease it a little it comes free easily.
Any questions? Please ask.
If you want to make a two piece mold just stick a couple of pieces of sprue into the bottom mold, a few mm's sticking out as a register for the top half. Pour the top half over the piece with another piece of sprue attached to the part for a pouring tube.
Easy peasy!
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Crimea_River
Marshal
Excellent, that explains a lot. Thanks!
Any special place you had to go to get the resin and mold materials? Did you use expensive purpose-built materials or did you find a cheaper alternative?
Any special place you had to go to get the resin and mold materials? Did you use expensive purpose-built materials or did you find a cheaper alternative?
I have made "open face" molds to make one sided parts using nothing other than a small tube of black RTV sealent! Just stick your part to a piece of plastic and cover it with a blob of the RTV. Let it dry throughly and peel it off the the plastic and remove the "master". The resulting mold can then be situated in some modeling clay of anything that will support it. Now I have only tried this on small pieces and I imagine with a little more thought I could find an equally cheap "resin". I have used Allumilite in the past with excellent results but it was a little pricey to make it cost effective and I had to (at the time) buy it in large bottles.
Hope this helps!
Hope this helps!
N4521U
Colonel
Squadron has all the commercial stuff available. Here in Australia it took me some time to find everything. Have never tried the "alternatives" mainly because I used to build with a group in San Jose years ago and was introduced to the commercial stuff.
I used to work in a commercial sign shop in Fremont where they used to buy clear half Sphere buttons to hide the screw attachments for interior signs, 5.00 each! I stuck about 10 of them to the bottom of a box and poured mold rubber over them and used to cast 10 at a time Cheep!
I don't have pictures but I got a Verlinden P-51 cockpit set and didn't want to hack up the instrument panel part so I made a cast of this then filed away the surround part and used this for my Merlin's Magic panel. So the original is still intact, so now I can trade this for something I need.
The trick is to make the "box" as small as possible to conserve material. You could even "pack" the voids of the box to further save volume. The biggest trick is estimating "volume". Both is the mold material and the casting resin. Metering the two parts of both is the Real trick because the quantities are so small, like parts of of a quarter teaspoon each for itty bitty stuff. Gotta find little squeeze bottle to meter Drops at a time.
Sorry for rambling. Bill
I used to work in a commercial sign shop in Fremont where they used to buy clear half Sphere buttons to hide the screw attachments for interior signs, 5.00 each! I stuck about 10 of them to the bottom of a box and poured mold rubber over them and used to cast 10 at a time Cheep!
I don't have pictures but I got a Verlinden P-51 cockpit set and didn't want to hack up the instrument panel part so I made a cast of this then filed away the surround part and used this for my Merlin's Magic panel. So the original is still intact, so now I can trade this for something I need.
The trick is to make the "box" as small as possible to conserve material. You could even "pack" the voids of the box to further save volume. The biggest trick is estimating "volume". Both is the mold material and the casting resin. Metering the two parts of both is the Real trick because the quantities are so small, like parts of of a quarter teaspoon each for itty bitty stuff. Gotta find little squeeze bottle to meter Drops at a time.
Sorry for rambling. Bill
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- #15
Crimea_River
Marshal
Appreciate all your help guys. I think I'm set to give it a try once I find the materials and I get my part made.
N4521U
Colonel
Sorry for keeping this going, but I found one of the illustrations I wanted to display. Merlin's Magic does not have a stock cockpit and I wanted to recreate what is there. The kit part was just toooo simplified so I used the aftermarket part as a model but also didn't want to destroy what could be used later. Bill
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Crimea_River
Marshal
Thanks!
hawkeye2an
Staff Sergeant
Crimea, have you considered carving them from wood and vauforming them? Would defiintely be cheaper.
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Crimea_River
Marshal
No actually. Got any avice on how to do that? The tanks I want to do are about 8mm in diameter and taper to about 5 in the middle. Vacuforming would be in 2 halves I assume.
hawkeye2an
Staff Sergeant
Sounds like it would be fairly simple to do on a lathe. Do you have drawings/plans? Make the items in wood and then stretch form (google vacuum forming for how-to) over them with styrene or PTEG. Any good Hobby shop will have the materials. Check out my thread on homemade vac machine for another way to vacuform.
