Question on PPG DP48LF...

Im switching away from alodine... too messy, looks like ****, etc. I saw this PPG stuff being used on rv7factory.com and like the way it looks... So my question is, will this stuff be efficient? Better or just as efficient as Alodine? I plan on doing all internals and the inside skins... leaving the outside skins bare for now until the day comes when she gets a paint job... And how much of the plane can I get done with a quart of this stuff? Here is what I'm looking at buying:

DP48LF Primer (quart)- https://buyat.ppg.com/refinishProdu...roductID=50798ced-3499-4eb5-9787-2db7e520df08

DP402LF Catalyst (pint)

DT870 Reducer (quart)

It is a good primer, but....

You still need to properly etch the aluminum with alodine or appropriate self etching primer. I have used this product and it is very good as an epoxy primer/sealer, although no where near as good as the original DP40 which was regulated off the market.
It works very well over Sherwin Williams Self Etching primer (Van's standard). You do not need to top coat it as it is a sealer as well, however it takes a top coat well.

JonJay said:

You still need to properly etch the aluminum with alodine or appropriate self etching primer. I have used this product and it is very good as an epoxy primer/sealer, although no where near as good as the original DP40 which was regulated off the market.
It works very well over Sherwin Williams Self Etching primer (Van's standard). You do not need to top coat it as it is a sealer as well, however it takes a top coat well.

Click to expand...

geez... this is really becoming a PITA. So I need to spray on a self etching primer, then the PPG primer? All this spraying... does it not change the diameter of holes/clearances?

Can I just use the rest of the alumiprep 33 I have? scuff everything with scotchbrite pads, alumiprep, dry, primer, rivet?

DP48LF

Daniel, take a look at the instructions for the DpxxLF series. I believe they will tell you to etch your surface (Alumaprep) and "alodine for additional adhesion". Your call on the alodine.

In my case, we're using new aluminum, and alodine is a nasty chemical to deal with, so I opted to just etch and prime. I've had good luck with the DP48LF stuff on my -7 and would use it again. I've had no chipping or other issues with primer coming off etched metal. Properly thinned out, it does lay down nice and smooth and I used a cheap Harbor Freight HVLP gun (worked well for primer).

All-in-all, I think I've used about 3 quarts for the entire thing. One for tail and some of the wings, another to finish wings and some fuse, then a third to finish the fuselage. It's going to take some time for the build so you'll probably want some fresh primer along the way.

Anyway, this is my opinion only.

Daniel,

The DP48LF is really tough stuff, but it is a major PITA (IMHO).

As far as spraying self-etching primer down first; I guess that is an option, but I have choosen to prep the AL with an cleaner/etcher. I use AFS (now Stewart Systems) etching cleaner, but you could also use Alumiprep or similar. You need to scuff, wash and etch the parts prior to priming, so there is a lot of work involved.

If I were to do it all over again, I wouldn't use it, I would use self-etch spray can primer only. But keep in mind I live in a dry climate.

One thing to keep in mind is that when mixed with the reducer, the DPxxLF becomes a sealer, which is good for internal parts, but may not be the best idea for exposed parts that will receive paint later on.

I am going to PM you my office number and cell number... if you want, give me a call when you have a few minutes and I will offer some additional advise.

I hate to jump in and muddy the water, and I DO NOT want to start a primer war, but...

Let's assume you've already decided to use a primer on all interior surfaces, so you just need to settle on a brand/process. The DP stuff is very good as a true primer (under paint) but was not designed for your intended purpose. I'm not saying it won't work, just that it wasn't made for this. The biggest drawback that I can see with it is that it is not particularly solvent proof. I know folks will say otherwise, but I know first hand that you can remove cured DP quite easily with a rag and acetone. Another issue is that it dries kind of slow and remains somewhat soft for quite a long time. IMHO you should go with the AKZO kit that Spruce and others sell. It's a gallon of primer, a gallon of catalyst and is an easy mix of one to one. Sprays extremely well, dries to touch in about ten minutes and you can assemble parts the same day you prime them. It was designed for our purpose and is VERY solvent resistant.

Now as far as pre-prime procedure goes, you've got choices. Clean is really the most important part, so use some solvent or soap to get off oily film and similar junk. The surface should be roughed up, so either etch or scuff. I suspect the etch actually does a better job at the micro level, even though to the naked eye the scothbrite seems to do more. I personally use the etch and sure can't think of any reason to do both. Alodine will help protect and promote adhesion, but the fact is that the primer won't come off even if you try, and most of these pieces are alclad anyway. I've alodined everything, but I could see skipping it if health issues are a concern.

I know that this post is gonna get a lot of opposing opinions, but I'm speaking from actual experience with the above named products. Best of luck and if you think this is a PITA wait til you get to the cowl

All I do is take the alclad off with a mix of Dawn liquid dish soap and water using a Scotchbrite pad.
Rinse well ... let sheet off till dry (any shiny part needs to be gone over again).
Then I shoot with self etching primer.
Done.
(Etch \ alodine \ prime .... all small parts)
Everything is primed as I live here on the Tx. gulf coast.

Steve (fuse)81604

FWIW, I emailed PPG Technical a few months ago. They offered 6 different product application systems within the Deltron line, and stating there were others. The most popular:

Sand and clean aluminum.

Within 8 hours spray a single light coat of DX1791 wash primer.

Within 24 hours spray DPLF epoxy primer.

Within 7 days spray topcoat(s).

The above are time limits. The prefered time frame is much shorter start to finish, pretty much just enough to flash solvents. Minimum time can be found in the TDS for each.

Deltron technical data sheets available here:

https://buyat.ppg.com/refinishProdu...?BrandID=5d7b4ed7-f83a-4469-b68c-04551702a5df

Having said that, I suspect DPLF sprayed on a freshly sanded/cleaned aluminum surface will have good long term adhesion. Plenty of other good choices too.

Speaking for myself, the only caveat would be to stick with a paint system per the manufacturer's TDS; no mix and match if your primer choice will later get a topcoat.

I've known a lot of people who have had good look with the SEM Self Etching Primer. One part, easy to use : http://sem.ws/Catalog.asp?prod=139. I started with PPG DPX171 Self Etching Primer, it's OK, but the SEM seems to be tougher and easier to apply.

Not strictly applicable to the "interior primer only" question, but I took a few moments to look up the PPG technical email I spoke of in a previous post. My particular interest was basecoat/clearcoat exterior finishing. Should be helpful to someone. Note choice #6; nothing under the DPLF. Also see the note about DPX171 and DPLF.
---------------------------
Dear Dan:

Thank you for your interest in PPG Refinish products. Aluminum may be refinished by one of the following Deltron combinations:

1. Etch primer DX1791, DPLF Epoxy, DBC, Deltron Clearcoat of choice
2. Etch primer DX1791, DPS3055, DAS3025, DBC, Deltron Clearcoat of choice
3. Etch primer DPX171, DPS3055, DAS3025, DBC, Deltron Clearcoat of choice
4. DX533, DX503, DPLF Epoxy, DBC, Deltron Clearcoat of choice
5. DX533, DX503, DPLF Epoxy, DPS3055, DAS3025, DBC, Deltron Clearcoat of choice
6. DPLF Epoxy(2 coats) DAS3055, DBC, Deltron Clearcoat of choice

These are just some of the combinations. All told there are probably another 10 more. A lot would depend on whether or not sanding is necessary (DPS3055, K36, K38 all require sanding...). The most common combination involves DPLF Epoxy somewhere in the mix. Options 1 and 4 are the most common. The rest is up to you.

A few things to keep in mind:
1. You CAN NOT apply DPLF Epoxy over DPX171 Etch primer. The only Etch products that may go under DPLF are the DX1791 Etch primer, and the DX503 Aluminum Conditioner.
2 If you decide to use the Metal Treatments (DX533 & DX503), you can not use any other kind of Etch primer as well (DX1791, DPX171)
3. DCC Concept Acrylic Urethane Single Stage may be used in place of DBC basecoat if you decide not to clearcoat.

If further assistance is required, please contact us at the Technical Service number listed below or visit our website at www.ppgrefinish.com.

PPG Technical Service office is open Monday - Friday, 8:00-6:00 EST. This office can be reached at 800-647-6050 or FAX 440-572-6772. The E-mail address is - [email protected]

b17fe said:

All I do is take the alclad off with a mix of Dawn liquid dish soap and water using a Scotchbrite pad.
Rinse well ... let sheet off till dry (any shiny part needs to be gone over again).
Then I shoot with self etching primer.
Done.
(Etch \ alodine \ prime .... all small parts)
Everything is primed as I live here on the Tx. gulf coast.

Steve (fuse)81604

Click to expand...

No way are you taking off the alclad, only dulling the shine. A very common misconception.

Les,
I this is the product I use for my self etch.
Your right... great stuff.
Steve 81604