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Poor mans propspeed


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OK I have been playing and may or may not be on to something. Time will tell. Anyone is welcome to try if they want, but I am still at an experimental stage and it may not work at all, so tryer beware.

I had been cleaning off some silicon on the bungs of some floats at work and normally any thinners does a poor job of cleaning Silicon. This time I used Epoxy thinners and noted that the Silicon came off cleanly. Time marched on and I was working on another project with Silicon and remembering that Epoxy thinners dissolved it. I thought about this idea and if I could make a paint from it for the prop. I mixed some epoxy into the Silicon and made a thick paint and painted it onto a plate of Bronze I had. A few days latter it was dry and I tried peeling it away. It peeled right off. Hmmm, how to make it stick well would be a key. So having some paint in a spray can I sprayed another piece of plate and while the paint was not completely dry, I then painted on the Silicon. A few days later it was dry and felt really good and I could not pull it off.

So today I took the idea a step further. First off, I thought what about Epoxy Resin painted on and when it was tacky, then apply the Silicon. It turned into a real mess and I decided to wipe the prop down and start again. I think I have nailed it this time, so here is what to do if anyone is interested in playing.

Take one tube of clear 100% neutral cure RTV Silicon. I don't think Acid cure will work, but could be wrong. The reason is that Acid cure gives off Acetic acid as part of the curing. The primer I used has acid in it and it's possible it may react and cause the Silicon not to cure properly. I have not tried so can't say for sure. Also, I decided to go for pure silicon instead of MS types (MS=Modified) as MS has other fillers in it that may also cause problems with curing. Remove all the Silicon from the tube and put into a small mixing container and slowly add a little Epoxy thinners. About 10% is all that is needed. Stir for awhile. Slowly the Epoxy thinners starts to dissolve the Silicon and you mix it till you have a thick'ish paint, but if you tip the pot on its side, the stuff will run.

Next clean down the prop. I used a 60grit disc and grinder and cleaned all the old propspeed off down to shiny prop. Next, clean the prop with some thinners. Then I used some Phosphoric acid to clean the Bronze further. Basically wipe it on with a cloth and wipe it off. This process may or may not do anything. Then I sprayed on some PA10. Now Wattyl has an etch primer I really like. I goes as hard as hobnails and I wish I had some. But the chandlery had only PA10. I sprayed a liberal coat on and just as it was drying off, I then painted on my Silicon "paint". I am going to let that dry overnight and then maybe paint another coat on tomorrow if it looks like it needs it. Although I am not sure how well another coat will adhere to the first. Silicon does not stick well to silicon once it is dry, but maybe the Epoxy will allow it to bond to one another.

So excitedly I await the outcome. Hey, it's worth a crack Nigel.

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I had a slightly better idea, but the cost was more and I figured if it was going to get expensive, one may as well use the proper product. The slightly better idea would be to use a two component mold making Silicon. Much harder wearing. But I could only find it retail and thus I don't think worth the risk of it failing against using a DIY product like Pellor Clean.

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I wonder if RTV silicone is actually a lubricant rather than a sealant even if dissolved.

There are various forms of silicones. As I understand it silicon as a lubricant comes in long chains of silicon alternating with oxygen so it is actually a silicon compound not strictly silicon although it is commonly referred to as such.

I had the same idea working on a 3 part system. I am not sure the etching primer is required although it would probably be better. Most seem to work with a layer of epoxy followed by a layer of epoxy lubricant mix applied before the first completely hardens. I was going to use Dow silicone teflon spray which has some hydrocarbons which seem to be volatile so it dries, as the source.

I have used the peller stuff with good results, however the small pack would do large props or several small ones. Unless it can be stored for some years which I doubt or shared I doubt it is more economical than having the alternative done professionally.

These systems need out of water drying for a day or more depending on temperature.

I did try to get the peller stuff again but could not get a reply from the agent to an e mail.

I have not tried it yet as I am out of action at the moment.

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Why not use acid cure Wheels?

As I said in my original post, I wasn't sure how Acid cure would go when I was using Phosphoric acid in the etch primer. It could well be OK and in that respect, even better, but I would rather try it on a piece of plate beforehand and see.


I wonder if RTV silicone is actually a lubricant rather than a sealant even if dissolved.
We have been doing a lot of study on Silicons and Polyurathanes just recently, for a totally different project I have been working on.


Firstly, this subject is far more complex than what I am briefly describing here.


Silicone and Silicon are two different things although both come from the base material Silica, which is a Beach Sand. However, the difference is so far removed, it is like saying Epoxy resin comes from Crude OPil and Synthetic Oil comes from Crude Oil. True, but two very different chemicals that had Crude Oil as their Base product to engineered from

RTV simply means "Room Temperature Vulcanizing", so there is nothing really special there. All Silicons are two component. It's just that the stuff you get in the Tubes has a particular part of the Curing process "on hold" till they are out of the tube and exposed to the Air. It is also why there is a shelf life with them. The two components that cure silicone are Tin and Platinum. Neutral cure requires the moisture in the Air to start the curing process and Acid Cure evaporates Acetic Acid.

You can get separate two component Silicons and these come in various hardness ratings using the Shore Hardness rating. Standard RTV Silicon in the Tube from the hardware has a "Shore A 27" hardness. 2 components range from 15 up to 40.

The big issue with all Silicones is that nothing sticks to cured Silicone, even Silicone. Pure Silicone does not adhere well to other substrates either and that is why you get MS (Modified Silicone) to improve performance.

Silicone Lubricants are completely different animals again. That is where the long thin chains that slip past each other comes into the picture.

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