[llavalle]

Tonight, I had my first encounter with black dead, AKA pro-seal.

I working on my first tank but because I just had my pre-close inspection (we still have those in Canada) on the tail, I finished the trailing edge on the left elevator and installed the foam ribs in the trim tab.

I can't believe how much this stuff is sticky...

I've got a couple of question :

1-I've heard that most people keep the stuff cold to preserve it better. Cold meaning the freezer or the refrigerator? It was in the refrigerator and it was really hard when I opened it. As it got hotter, it became a bit more flexible...

2-Do you need a respirator while you use pro-seal? I did not put on my 3M mask and the smell was not really bad. I suppose MEK is the reason to use a mask?

3-Anything other than mek working to remove pro-seal? I'm waiting for a shipping quote from Spruce because it's HazMat. Most sellers won't ship to Canada, I'm kind of stuck with Spruce Canada. I've tried Acetone but it does not seem to do anything. Maybe lacquer thinner?

4-How much time does it need to cure? The reason I ask : how much time do I have to wait before removing the alum. angle on the trailing edge?

5-I put a bit too much pro-seal on the edges of the wedge (see pic below). Is this stuff easily removed when it's cured? Using a file maybe?

Thanks!

 

[Lionclaw]

1 - Refrigerator. Yes, it's harder to work with cold, but it warms up quick when you start to mix it.

2 - I don't use one. I don't find the smell too unpleasant, but I have no idea if not using one is "dangerous".

3 - I have good luck with acetone. I buy bundles of washcloths. Dip it in a bowl of acetone and rub away at whatever has proseal on it. It even works after the proseal has started to harden. I wear 2-ply nitrile/latex gloves when using acetone.

4 - It is entirely dependent on the temperature where it is drying. If it was properly mixed, and in a 70+ degree F room, I would remove the angle after 2-3 days. I've done some when it was cold and it took almost 2 weeks before the beads felt solid enough.

5 - I would leave it until it cures and then carefully run a razor blade down the trailing edge. I did that on mine, and found that I preferred having a bead to cut off rather than not having enough and trying to back-fill. I also attacked my angle with boe lube before attaching it to the trailing edge. It will make it much easier to remove later on.

It was nice meeting you at Osh - I hope things are going well!

 

[llavalle]

[...]
4 - It is entirely dependent on the temperature where it is drying. If it was properly mixed, and in a 70+ degree F room, I would remove the angle after 2-3 days. I've done some when it was cold and it took almost 2 weeks before the beads felt solid enough.
[...]
It was nice meeting you at Osh - I hope things are going well!

I was about to edit my post to add the shop temp. I've been using the A/C for a couple of weeks now but I turned it off for the pro-seal session. I just went in to check the temp, it's around 75F now. It should get hotter tomorrow.

Thanks for the hints. It was nice too meeting you at Osh. Seems like I'm a easy to recognize guy: you did while we were waiting at the Van's tent and at the Van's banquet, Doug stopped by me to say hi! He said something like "hey, you're Phil, that guy from Qu?bec"! I did not know I was a super star like that

 

[Rick6a]

1-I've heard that most people keep the stuff cold to preserve it better. Cold meaning the freezer or the refrigerator?....

Unmixed proseal components should at least be be stored in a cool dry place. For long term storage, refrigeration is wise. Normally, in production shops, premixed proseal is stored in deep freezers (-40?-80?) until shop use.

2-Do you need a respirator while you use pro-seal?

No. It's "aroma" may be an acquired taste but is completely harmless. Some people can develop an allergic reaction to proseal but such instances are rare.

3-Anything other than mek working to remove pro-seal?

While other solvents can and have been used, some even outlawed such as trichloroethane, MEK is the most efficient, cost effective and widely available solvent for removing uncured proseal. Since it does pose a health risk, provide plenty of ventilation. Wearing a mask is recommended.

-How much time does it need to cure?

Cure time is temperature and humidity dependent. To accelerate the cure, some shops place a heat lamp near the work. Lab verified and calibrated temperature probes are placed around the proseal to insure the temperature does not exceed a given amount. I do not recall what exactly what the specific temperature range is...135?-145? seems about right, but don't quote me on that.

5-I put a bit too much pro-seal on the edges of the wedge (see pic below). Is this stuff easily removed when it's cured? Using a file maybe?

NEVER use metal of any sort to scrape away excess proseal. Always use a plastic, plexiglas, or wooden scraper. Fully cured, the squeeze out of proseal in your picture is very easily removed...even with a wooden tongue depressor, its edge sanded down to a beveled edge will easily remove that proseal. Clean up the remaining residue with a towel or rag soaked MEK. Cheesecloth works very well, more efficient than using towels or cotton rags.

 

[llavalle]

NEVER use metal of any sort to scrape away excess proseal. Always use a plastic, plexiglas, or wooden scraper. Fully cured, the squeeze out of proseal in your picture is very easily removed...even with a wooden tongue depressor, its edge sanded down to a beveled edge will easily remove that proseal. Clean up the remaining residue with a towel or rag soaked MEK. Cheesecloth works very well, more efficient than using towels or cotton rags.

Thanks for the additional info. I was wondering if your comment about using metal applies to cured pro-seal as well? I need to file the trailing edge of the elevator wedge. Since it's now full of pro-seal, how should I proceed?

 

[islandmonkey]

Why?

NEVER use metal of any sort to scrape away excess proseal.

Can you explain why not?

 

[Rick6a]

Thanks for the additional info. I was wondering if your comment about using metal applies to cured pro-seal as well? I need to file the trailing edge of the elevator wedge. Since it's now full of pro-seal, how should I proceed?

I'm not sure what you mean by having to "file the trailing edge of the elevator wedge." My response is limited to acceptable shop practices for general proseal removal only. I do not know why you have to do any filing. Is filing the metal structure a necessary step in the construction process? If so, then by all means....file.

Limiting my response to a narrow discussion of proseal "points to ponder" fully cured proseal squeeze-out (as shown in your photograph) is easily removed as previously described. Simply put, proseal, fully cured or uncured should only be scraped off structure using a non metallic tool.

 

[Lionclaw]

Rick, what harm will a metal tool cause? Any reason not to cut proseal? (speaking strictly for use in trailing edges here)

I've tried using a plastic putty scraper to remove cured proseal from a trailing edge, but it pulled proseal out from the joint and also left a jagged edge. If the suggestion is to always remove excess proseal before it cures, then I can understand that. I just found that when doing my trailing edges leaving a bead and slicing away the remains made for a nicer looking edge.

 

[Rick6a]

....what harm will a metal tool cause?....

Its a corrosion control thing. Using a metal tool to scrape away proseal virtually guarantees you will scratch the surrounding surface. If not polished out and retouched with alodine etc., surface defects can lead to corrosion or stress risers. BUT, if you apply alodine or any other chemical to the surface of exposed proseal, even spit (no kidding), the proseal is considered contaminated and long term performance is degraded to some unknown degree. Of course, as homebuilders we are perfectly free to do anything we want, but using a metal scraper to remove proseal is a major no-no in the production world and I believe we all can learn from that. This is but one example to illustrate what I have said in the past. That is, I would be far more comfortable buying a used certificated aircraft than a given homebuilt. With a certificated aircraft, you are assured at least some minimum level of quality control went into its construction. All bets are off when the aircraft is amateur built so an extra-extra detailed inspection of its built-in quality is advisable.

I'm not sure why you had trouble removing cured proseal. For instance, I installed this empennage fairing with nothing more than proseal. After taping the fairing into final position, the proseal oozed out from all around the fairing. That is exactly what I wanted. Days later, when the proseal was more or less cured, I scraped the edges clean with a plastic scraper. The proseal came off very easily. No way would I use a metal scraper to remove the cured proseal and in doing so unavoidably damage the surrounding alclad.

 

[llavalle]

I do not know why you have to do any filing. Is filing the metal structure a necessary step in the construction process? If so, then by all means....file.
[...]
Simply put, proseal, fully cured or uncured should only be scraped off structure using a non metallic tool.

Yes, it is a step in the construction process. I need to remove the excess trailing edge material from the wedge to make it flush with the skin.

As with others, I'm wondering why we should void scraping pro-seal with a metallic tool? Can you explain further?

Thanks.

 

[llavalle]

Sorry for the question about the reason : I was typing when you replied. I would edit the previous post but the stupid firewall at work is blocking the DHTML for the "quick edit".

That make sense. Thanks.

 

[Lionclaw]

Its a corrosion control thing. Using a metal tool to scrape away proseal virtually guarantees you will scratch the surrounding surface. If not polished out and retouched with alodine etc., surface defects can lead to corrosion or stress risers.

I can see why you wouldn't use a metal tool for your fairing application. It would obviously cut/scratch the skins. But, I still don't see how there is any harm in cutting a bead off a trailing edge. As far as I know, there is no alclad on edges of skins, and hence nothing to be scratched away. I'm happy with my trailing edges. If I had to do them again I'd do it the same way.

 

[llavalle]

A small note for non rv-9 builders :

On the RV-9, the elevator skins are pre-bent on the leading edge. Le trailing edge is opened and riveted using double-flush rivets on a wedge. The rudder is similar : there are 2 separate skins. The leading edge is bent to make the curve and the rear is attached the same way as the elevators.

During riveting, to make sure the trailing edge is not curved, you clamp in on a angle and apply pro-seal. When it's cured you remove the angle and rivet.

Because of this, the pro-seal is not critical in this application. Any glue would work.

Thanks for the replies, it helped a lot!

 

[spaceman_spiff]

Been a little while since I've messed with it, but I like the smell of "pooky." But it is an acquired taste...probably comes with the brain damage of the MEK.

Green 409, a red shop rag and some elbow grease will do a pretty good job getting it off your fingers, but for cleaning tools, surfaces, etc., you're probably best off with MEK.