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May 27, 2019, 10:48 AM
Scott
Pylonracr's Avatar
Jim, I will shoot you a PM or an email later today. Give it a try when you need PVA.

Scott
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May 27, 2019, 06:01 PM
Entropy is happening!
Jim.Thompson's Avatar
Quote:
Originally Posted by Roguedog
..............................
Where I'm located is very arid during the summer and I sometimes have to add 50 % water to the PVA to get it too spray correctly. It's not possible to spray it straight out of the gallon container at any time of the year where I live.

So that requires different ratios of water to PVA depending on the weather.
One possible adverse factor here might be the very high humidity. For example (off topic), I have been waiting for weather suitable for spraying acrylic lacquer for months. I have a run of low humidity days now...........I did some yesterday and will do some again today. Between the hours of 11:00 and 14:30 . By 16:00, the humidity will be too high and the paint will blush.
But I am clutching at straws here looking for an explanation of my real world experience and results and the diametrically opposite reported result of yours, Scott and a few others.
In fluid dynamics theory, taking into account surface tension and incompatibilities, a water based product on top of a wax is, by definition, a recipe for problems.

Quote:
Originally Posted by Pylonracr
Jim, I will shoot you a PM or an email later today. Give it a try when you need PVA.
Scott
Thanks Scott. Received and replied to.
Edit:
I will likely get around to trying the PVA application method you describe at a later date for a new mould.
However, for my old post cured and aged moulds, I will be sticking to wax only. Now I have plunged into the wax only way of moulding.
You may recall, my fully moulded Entropy was built from plug to mould to part using wax only.
However, I am increasingly hesitant to advise anyone else to use this procedure, as every stage is critical.
I have written about the stages elsewhere.

Jim.
Last edited by Jim.Thompson; May 27, 2019 at 06:10 PM.
May 27, 2019, 08:33 PM
Registered User
Roguedog's Avatar
Well it seems that your experience is contrary to Rexco's PartAll #10 TDS. You find it attached.

First thing is the TDS clearly says that PartAll #10 is soluble in water. This means you can create a "solution of PVA and water or use water to wash it off.

Just like some people can spray paint and some can not does not mean that your experience trumps their experience or the manufacturers. What I am hearing from you is that your way is the only way to apply composite techniques. Rexco I am sure has tested their products extensively.

You have decided not too use PVA because you have previously stated that you can't get the results me and others have stated that we have achieved. That's fine.

But just because you either lack the patience or ability to learn and use it does not mean that we lairs.

The facts for me are this:

I don't have the luxury to wait for a certain time of the year to spray PVA, paint, or primer.

When I want to spray something i investigate the information available, try the manufacturers recommended application precedures, and if that doesnt work experiment which takes time.

Maybe you don't understand that the word "arid" means hot and dry. Further down in PartAll #10 TDS it says--
In hot and dry climates the alcohol in PARTALL® Film #10 may cause the atomized stream to dry prior to arrival at substrate, creating a cobwebbing effect. This may be overcome by diluting PARTALL® Film #10 with up to 10% distilled water.
In the summer where i live the temps are regularly in the high 90's to low 100's or hotter with a humdity of 7 to 15%.

The very first time i sprayed PartAll #10 all is did was spray cobwebs, The Alcohol evaporated completely 3 inches from the spray tip.

I tried the recommended 10% dilution and still was spraying cobwebs that day. Humidity was 7% that day. Due to the high heat and the low humidity I ended up diluting the PVA with 50% water to get it to spray correctly. An extreme case yes. But I kept experimenting til i found a solution (mixture) that worked.

So far by following the manufacturers TDS and my own tenacity at experimenting I have gotten mirror finish results repeated even though you disagree.

Your real world experience does not mean it applies to the world as a whole. You saying "real world" doesn't mean that your experience is the definitive and only thing that matters. Sorry dude, your just not a presenting complete picture of the facts jsut your experience. The attached pic is an example of the mirror finish that can be achieved when you spray (thinned with water) PVA. That is what it looks like dry not right after spraying.

You where supporting my SR-7 molding and part making thread up to the point that i used PVA. then left a pointed post about how you where unsubscribing at the point. It was apparent to me at the time you weren't posting to support me. I can't read your mind and why you were so offended that you needed to even leave a post to say you were unsubscribing and in my opinion a very mean and petty thing to do to someone who's making a first attempt at composites.

If it was me, I had this great experience in composites, I would not just bale on someone's thread because of my dislike of their methods. Just because you can't or won't take the time to use PVA doesn't mean you should throw shade at those who do or bale on them with a nastily worded post. You could have just stopped following the thread. Oh yea. Just wanted to say thanks for your support.

One other point I want to make here is anyone who is looking at or thinking about trying composites. Jim must have the money to burn on high end permanent mold waxes and other composite products. More power to him.

I don't see the need to waste my money using products that would be suitable for long term manufacturing of hundreds of part pulls from a mold when you only gonna pull maybe 20 or 30 parts at the most. Totally a waste of money for those new to composite molding and part making when less expensive methods and materials will provide just as good a mold or part.

edit - I'd like to point out that yes that some of the water will displace the PVA if it doesn't evaporate before hitting the surface. I left a sprayed part over-nite and didnt realize til after the layup that the pva had pulled away from the sharp corners in the mold. For this reason I only spray the PVA on the day i do the layup.
Last edited by Roguedog; May 28, 2019 at 05:00 AM.
May 27, 2019, 08:39 PM
Entropy is happening!
Jim.Thompson's Avatar
Quote:
Originally Posted by Roguedog
........................................ What I am hearing from you is that your way is the only way to apply composite techniques...........................
But just because you either lack the patience or ability to learn and use it does not mean that we lairs.

...............................................
Nonsense! On both counts.
I said nothing of the sort. Nor did I imply it

Me thinks He doth protest too much.

Unsubscribing now.
May 27, 2019, 09:10 PM
Registered User
Roguedog's Avatar
Sorry for digression,

For the OP if your mold or wax is contaminated then PVA would have fish-eye'd as well.

The alternative is get in the habit of using a wax, grease, and silicone remover before applying the wax to the mold.

If the paint fish-eyes again then the wax is contaminated and needs to be tosed and replaced.

I've been painting my own cars for 50 years on and off. use a wax and grease remover every time.
For me it's just easier to paint the part after its made. Just my preface. IMO painting the mold is for backwards thinking people.

Oh yea. never had a mold stick to plug or a part stick to mold because i use PVA everytime. Also use epoxy resin exclusively so no parts stuck from styrene migration issues to worry about, e.g. green molds. They again aren't an issue when using epoxy resin. Epoxy resin molds should exhibit the same proberties new or old. Wax it, use PVA or not, then do the layup
Last edited by Roguedog; May 27, 2019 at 09:32 PM.
May 27, 2019, 09:24 PM
Registered User
Roguedog's Avatar
Geez present some facts get the same result. Only now it's bailing on the OP. Nice guy, Awsome support.

Glad he's not my dad God forbid.


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