ondarvr
Supreme Mariner
- Joined
- Apr 6, 2005
- Messages
- 11,527
Re: PB Explained
This has been covered in the past, but it?s probably difficult to find.
Cabosil, Aerosil . A type of silica that is used to thicken resin, not only will it make it thicker, but will also keep it from sagging, not many other things will do this. Not much strength, but most application don?t require much. Most putty formulas should include it to prevent sagging. Hard to sand.
Balloons, Micro spheres, glass bubbles. Will thicken resin, but won?t stop it from sagging. It will make a light and easy to sand filler.
Talc. Makes a very smooth putty, can be used with Glass bubbles and Cabosil to make a very easy to work with product. Talc doesn?t have good water resistant properties and can absorb water and cause the putty to fail sometimes. Automotive body fillers frequently use talc.
Milled fiber. Can add some strength to an otherwise weak putty. The longer the fiber, the more strength it adds, but don?t expect it to add a great deal of strength, just better than without it. The other issue is that as you add more the putty becomes harder to work with, the surface will be uneven and lumpy, longer fibers make it even harder to work with. There are several types of fibers, but glass is the most common. Not easy to sand.
CSM, mat. The longer fibers can add more strength, but again, don?t expect it to be as strong as resin and mat. You can?t get enough CSM mixed into a putty for it to increase the strength dramatically. It can also make the putty very difficult to work with because of the long fibers. One way to make it easier to use is to use a lower catalyst level to extend the gel time and also reduce the heat generated, then glass over it while the putty is still soft. You need to be careful or you will just push the putty around and mess it up while trying to get the air out of the glass.
The above items are the most common products used, there are others though
Other things you may have around that have been used at times, maybe not great, but can work in a pinch.
Flour. (out of the kitchen) Works to make it thicker and smooth.
Wood flour, (fine sawdust). Is used quite a bit by some people in DIY projects.
Baby powder (talc or cornstarch), it works.
Sand (from the sand box). It works, but you can?t sand it or do much else with it.
Just about any powder you can find will work, but again, possibly not well.
With any of these products the amount and ratios of each can be adjusted to meet the need. At one time I had some ratios that I used to make concoctions I liked, but I no longer have them, so I just blend as needed. As a rule it will take more Cabosil and less milled fiber (any fiber) than you expect it to the first time you play with it. You will also go from not quite enough to too much rather quickly, so don?t mix all of your resin in right up front, keep a little extra so you can add more if you add too much of something else and it becomes thick and unworkable.
You can insert the term ?PB? in place of ?putty? in anyplace you would like to.
This has been covered in the past, but it?s probably difficult to find.
Cabosil, Aerosil . A type of silica that is used to thicken resin, not only will it make it thicker, but will also keep it from sagging, not many other things will do this. Not much strength, but most application don?t require much. Most putty formulas should include it to prevent sagging. Hard to sand.
Balloons, Micro spheres, glass bubbles. Will thicken resin, but won?t stop it from sagging. It will make a light and easy to sand filler.
Talc. Makes a very smooth putty, can be used with Glass bubbles and Cabosil to make a very easy to work with product. Talc doesn?t have good water resistant properties and can absorb water and cause the putty to fail sometimes. Automotive body fillers frequently use talc.
Milled fiber. Can add some strength to an otherwise weak putty. The longer the fiber, the more strength it adds, but don?t expect it to add a great deal of strength, just better than without it. The other issue is that as you add more the putty becomes harder to work with, the surface will be uneven and lumpy, longer fibers make it even harder to work with. There are several types of fibers, but glass is the most common. Not easy to sand.
CSM, mat. The longer fibers can add more strength, but again, don?t expect it to be as strong as resin and mat. You can?t get enough CSM mixed into a putty for it to increase the strength dramatically. It can also make the putty very difficult to work with because of the long fibers. One way to make it easier to use is to use a lower catalyst level to extend the gel time and also reduce the heat generated, then glass over it while the putty is still soft. You need to be careful or you will just push the putty around and mess it up while trying to get the air out of the glass.
The above items are the most common products used, there are others though
Other things you may have around that have been used at times, maybe not great, but can work in a pinch.
Flour. (out of the kitchen) Works to make it thicker and smooth.
Wood flour, (fine sawdust). Is used quite a bit by some people in DIY projects.
Baby powder (talc or cornstarch), it works.
Sand (from the sand box). It works, but you can?t sand it or do much else with it.
Just about any powder you can find will work, but again, possibly not well.
With any of these products the amount and ratios of each can be adjusted to meet the need. At one time I had some ratios that I used to make concoctions I liked, but I no longer have them, so I just blend as needed. As a rule it will take more Cabosil and less milled fiber (any fiber) than you expect it to the first time you play with it. You will also go from not quite enough to too much rather quickly, so don?t mix all of your resin in right up front, keep a little extra so you can add more if you add too much of something else and it becomes thick and unworkable.
You can insert the term ?PB? in place of ?putty? in anyplace you would like to.
.. sometimes a good understanding is what keeps me going ..