Will RTV silicone bond with latex?

[ob1al]

Hi all

I'm trying to repair a latex piece (an Illusive Yoda actually) that has been partially sun damaged at the back of the head and ears and partially torn by...a dog...or something... :confused

Anyway, I'm planning to use expanding foam to fill in the missing chunks, then posibly use some RTV silicone to create a 'skin' over the filled areas before painting.

What do you think? Will this work?

Will the RTV bond to the existing latex 'skin'?

 

[weaselflinger]

In my experience, the silicones I've used do not bond to latex

 

[seknewb]

The RTV will bite into the foam (to an extent) because it's pourous, but almost certainly won't stick to the latex. You would need to lay down a thin layer of caulking first to get any bite at all. You also have the issue of painting it afterward. Silicone caulk based paint is about the only thing that's going to stick for any period of time, and even that will come off with handling...

If it's in bad shape, it's going to continue to deteriorate no matter what you do. I would spend the extra $100 (or so) and make a quick silicone snap of it and cast it in urethane and rigid foam. Then it'll never rot on you...

 

[ob1al]

That's an interesting idea - how would I go about that exactly? I've got a little bit of experience of making RTV moulds, is the process basically the same?

 

[seknewb]

Originally posted by ob1al@Jul 16 2005, 08:43 AM
That's an interesting idea - how would I go about that exactly? I've got a little bit of experience of making RTV moulds, is the process basically the same?

[snapback]1034708[/snapback]​

Get some RTV and some fast catalyst from your distributor. If you can't find the fast catalyst, try Burman Industries in LA ( www.burmanfoam.com ) or Alcone in NY.

Keeping it simple, quick, and dirty....

Spray some Crystal Clear on the piece to act as a barrier and seal it. You might want to throw a light coat of spray on mold release for ease of removal later.

Brush a thin layer of the fast catalysed RTV onto the piece, making sure to get all of the details. Build it up as it thickens. Add another thin layer or two, and then mix up a larger batch of RTV (fast-catalysed) and thicken with cabosil. Fill all of your undercuts and build up an overall thickness of maybe 1/4 inch over the entire piece. Get a cup of alcohol and some rubber gloves and massage it smooth as it sets. Once that's done, the easiest "throw-away" would be to make a simple plaster bandage jacket as needed depending on the piece... probably front and back. Don't forget to release the seam/overlap between the 2 parts...

Once everything is good and solid, carefully remove (cut up the back if needed), slush urethane into it and foam.... DONE. I've done this entire process in as little as 2 1/2 - 3 hours.

Far quicker and simpler than a full matrix, especially since you're just trying to replace the one rotting piece.


If you've got specific questions, PM me. I usually check the site 3-4 times a week.

GOOD LUCK ..

 

[ob1al]

Originally posted by srne+Jul 16 2005, 02:04 PM--><div class='quotetop'>QUOTE(srne @ Jul 16 2005, 02:04 PM)</div>

<!--QuoteBegin-ob1al

@Jul 16 2005, 08:43 AM
That's an interesting idea - how would I go about that exactly? I've got a little bit of experience of making RTV moulds, is the process basically the same?

[snapback]1034708[/snapback]​

Get some RTV and some fast catalyst from your distributor. If you can't find the fast catalyst, try Burman Industries in LA ( www.burmanfoam.com ) or Alcone in NY.

Keeping it simple, quick, and dirty....

Spray some Crystal Clear on the piece to act as a barrier and seal it. You might want to throw a light coat of spray on mold release for ease of removal later.

Brush a thin layer of the fast catalysed RTV onto the piece, making sure to get all of the details. Build it up as it thickens. Add another thin layer or two, and then mix up a larger batch of RTV (fast-catalysed) and thicken with cabosil. Fill all of your undercuts and build up an overall thickness of maybe 1/4 inch over the entire piece. Get a cup of alcohol and some rubber gloves and massage it smooth as it sets. Once that's done, the easiest "throw-away" would be to make a simple plaster bandage jacket as needed depending on the piece... probably front and back. Don't forget to release the seam/overlap between the 2 parts...

Once everything is good and solid, carefully remove (cut up the back if needed), slush urethane into it and foam.... DONE. I've done this entire process in as little as 2 1/2 - 3 hours.

Far quicker and simpler than a full matrix, especially since you're just trying to replace the one rotting piece.


If you've got specific questions, PM me. I usually check the site 3-4 times a week.

GOOD LUCK ..

[snapback]1034719[/snapback]​

[/b]

Brilliant, thanks a lot for your help. :thumbsup

Regards

Al

 

[seknewb]

No problem... Like I said, PM me if you get stuck...

I've gradually been doing this to all my latex stuff. Won't buy the soft stuff any more myself for this very reason...

Even the new silicone pieces are going to have the same trouble down the road... Rubber rots, simple as that....

 

[ob1al]

Originally posted by srne@Jul 16 2005, 04:03 PM
No problem... Like I said, PM me if you get stuck...

I've gradually been doing this to all my latex stuff.  Won't buy the soft stuff any more myself for this very reason...

Even the new silicone pieces are going to have the same trouble down the road...  Rubber rots, simple as that....

[snapback]1034774[/snapback]​

One more question - would a plaster of paris mold work on the latex head / hands?

I only need the one good pull out of all this and if its possible, it would be a cheaper alternative than RTV. Is it possible to make a 2 piece Plaster mold for something like this?

 

[seknewb]

Originally posted by ob1al+Jul 17 2005, 07:02 AM--><div class='quotetop'>QUOTE(ob1al @ Jul 17 2005, 07:02 AM)</div>

<!--QuoteBegin-srne

@Jul 16 2005, 04:03 PM
No problem... Like I said, PM me if you get stuck...

I've gradually been doing this to all my latex stuff.  Won't buy the soft stuff any more myself for this very reason...

Even the new silicone pieces are going to have the same trouble down the road...  Rubber rots, simple as that....

[snapback]1034774[/snapback]​

One more question - would a plaster of paris mold work on the latex head / hands?

I only need the one good pull out of all this and if its possible, it would be a cheaper alternative than RTV. Is it possible to make a 2 piece Plaster mold for something like this?

[snapback]1035175[/snapback]​

[/b]

Sure, you can make a plaster mold, but you'll only be able to pull more soft parts from it... latex/silicone/etc.. You'll be starting over again in a few years...