Finding companies in california that will do adhesive primer prep.

[berkshire]

This is what I am asking about:
Adhesive Primers / BR-127: By definition, adhesive primers are intended to help enhance the bond strengths of metal, primarily aluminum. Such primers can prevent hydrolysis of oxide layers, Improve hydrolytic stability at the adhesive to metal interface, and protect prepared surfaces from further oxidation. Properly prepared/primed surfaces have an indefinite shelf-life, allowing convenient bond scheduling. Permanently bonding various substrates can be an extremely difficult job. However, by using an adhesive primer high strength bonds can be easily and quickly achieved. Lap-shear and T-peel testing is performed “in-house” to validate the quality of applied adhesive primers.

I have an up coming job on a sheet metal sailplane where the skins are wet bonded to the structure, then held in place by rivets ( Chicken Fasteners.)
Having gone through the treadmill of getting a good bond through surface prep in the past, I know there are companies that will wash etch , prime and send you a skin ready for gluing, I am all for letting somebody with a good QA program do this for me.
My problem now being retired is that my contact list is getting out of date. I know of one company in Oxnard Ca. I am wondering if anybody knows of companies that do this south of Los Angeles Any leads will help.

B.E.


You are judged not by what you know, but by what you can do.

 

[WKTaylor]

Berkshire... probably too much thinking here...

"...I know there are companies that will wash etch , prime and send you a skin ready for gluing..."

1. Surface prep for high quality/durability [bet-your-butt] adhesive bonding must do more than 'wash-etch' [aluminum, in prep for application of adhesive primer].

The primary aluminum pre-treatments I am familiar with in descending order of preference are...

Phosphoric Acid Anodizing [PAA], Typical ASTM D3933.

Chromic Acid anodizing or thin-film Sulfuric Acid anodizing MIL-A-8625 [Type I or IIB respectively]

Abrasive-clean and silane surface treatment [several commercial preps, processes].

Pasa-Jell 105 + chromate conversion coating [fluoride acid version].

2. Caution, BR-127 should be applied to a VERY thin dry-film thickness. A mist-coat 0.0002-0.0004" DFT is just about perfect... but is so transparent that the substrate is readily visible and 'just doesn't' look right to most painter familiar with application of traditional [corrosion inhibiting] primers. Heat-cure of the primer is necessary since paste adhesives are applied at RT.

3. Make sure You specify packaging for the primed part that is free of any traces of contaminates [dust, oil, grime, moisture, etc... and that You handle the part with clean cotton gloves.

4. Bondline thickness control using conventional paste adhesives is important. A bond line of 0.005-to-0.010 is usually considered 'nominal'. Some paste adhesives have an inert filler for this purpose... otherwise I suggest adding glass or phenolic microspheres ['bubbles'] or 'fresh/unused' 0.007-Dia glass beads [~2-to-5% of adhesive mass] thoroughly mixed in to ensure bondline control.

5. Fud-4-Thot NOTEs.

5.1 ALL corners and edges should be generously rounded to avoid sharp corners; and all sharp edges should be generously deburred/radiused. Sharp corners tend to lift/peel; whereas rounded corners have no 'focus point' for peel loads. Rounded edges pick-up an adhesive fillet which reduces 'peel' tendency.

5.2 Bondline thickness control comments.

At one time I also advocated use of 'cleaned nylon thread' [IE: ~8# test fishing line], placed/woven across the epoxy paste-adhesive surface, just prior to installing outer parts [doublers, patches, etc].

When available, virgin scrim-cloth from a pre-preg adhesive vendor [or sub-tier vendor] provides excellent bondline thickness control when 'wet-out' on both sides with epoxy resin just before application to the bondline.

In general, glass beads work better that threads or scrim for average mechanics.

5.3 Apply adequate thickness of adhesive across the part... and press firmly in-position starting in the middle and working outwards. Excess adhesive squeeze-out around all edges is an indicator of a high-probability that there is good-adhesive fill [minimum voids] between parts.



Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[berkshire]

Thank you for that information Will.
The paste adhesive will most likely be Henkel EA9309 or a similar high peel strength epoxy. the skins are .025" aluminum 25'-0" long by 18" wide
.
B,E,

You are judged not by what you know, but by what you can do.

 

[MintJulep]

For your reference:
thread728-337362
thread2-419964
thread2-394945

 

[berkshire]

I just managed to get a materials list for this aircraft which was built in the 1970s and find the original bonding resin was ARALDIT AW 134 B / HV 997. which was most likely state of the art at the time. That takes some but not all of the pressure off to get a good bond , because we now have resins that are much better than that. Next thing is to get approvals from the manufacture for a substitute resin with better performance.
B.E.

You are judged not by what you know, but by what you can do.

 

[rb1957]

make a test piece ?

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

Berkshire...

EA 9309 appears to be an old formulation... it is not on my high list of EA adhesives. Per the TDS I downloaded it has decent peel... but other properties fall-off very quickly with [+^]Temperature... at 180-F properties are barely breathing.

EA 9309

https://files.engineering.com/getfi...nkel-Hysol_EA_9309NA_AERO~Paste_Adhesive~.pdf

Suggest You consider using EA 9394 [or the old stand-bye EA 934NA]... I've had excellent experience/performance with these over many years....

EA 9394

https://files.engineering.com/getfi...ol_EA_9394_Aero~Paste_Adhesive~-65F_+350F.pdf

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[berkshire]

Right Will ,
It has been around since the middle 70s, which is why I thought this aircraft was built with it, The latest version is EA9309.3 NA .
The original formulation used asbestos fiber for bond line control , they took that out, and use glass micro balloons hence the NA designation for no asbestos.
The original reason for using it was because of the peel strength at the cost of other properties like heat deflection.
Since the TDCDS calls for the aircraft to be only painted white , this is not a concern. The peel strength is the major benefit of this adhesive 45ft lbs compared to 5 lbs for the EA9394 .

But this does not answer the question where do I get these sheets cleaned etched and primed ?
B.E.


You are judged not by what you know, but by what you can do.

 

[WKTaylor]

Berkshire...

Odd.. I could NOT find TDS for EA 9309.3NA on Henkel website... only EA 9309 Aero... but found MSDS and vendors willing to sell it. The Henkel website failed to return any TDS. IF You have the TDS for EA 9309.3NA would appreciate a link.

NOTE. Trick-of-the-trade...
Peel resistance can be substantially improved by using 'longer' and 'thinner' edges: IE sine-wave edge-pattern and/or with tapering-thickness to the edge.

PS... trivia... from tech support...

EA = EPON Adhesive [originally developed by EPON decades ago]

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[berkshire]

WKTaylor,
Will, The information is now on the Loctite website, this is a distributor,

https://www.ellsworth.com/products/...te-hysol-ea-9309.3na-epoxy-adhesive-1-qt-kit/

I may be wrong on this but I believe the Epon link was because the forerunners to Henkel started with Shell Epon 828 resin and added Butyl rubber to the formulation to get the peel strength.
B.E.

You are judged not by what you know, but by what you can do.

 

[blakmax]

Berkshire

I would have thought that a change of adhesive would require a full certification program following AC 20-107 B "building block" approach.

I also think that somewhere in the back of my mind California banned the use of hexavalent chromate treatments such as BR 127 because of the link to cancer but I may be wrong. I also strongly suggest that for QA you add the wedge test ASTM D3762 but with amended acceptance criteria as stated in DOT/FAA/AR – TN06/57, Apr 2007, Best Practice in Adhesive Bonded Structures and Repairs. Static strength tests will only tell you of the strength at a given time, whereas the wedge test will give a short term indication of the potential for longer term hydration effects on bond longevity.

Regards

Blakmax

 

[berkshire]

Hi Max,
I am trying to find companies that will clean and prep for gluing I have found one company in Oxnard Ca , but I did not want to travel that far. This job is a field repair where existing corroded skins are removed, then replaced with New 2024 T3 alclad skins . Which of course have to be prepped, one to prevent the new skin corroding , and two to have a bond for the new adhesive so that I do not have to do further prep.
BR127 is an epoxy coating ,BR® 127 corrosion inhibiting primer is a modified epoxy primer some Zinc chromate primers are still permitted But California is leaning more to Strontium chromate primers . Br127 is the industry standard for high performance corrosion inhibiting primers and has been used in virtually every commercial aircraft built since its introduction. BR 127 primer can be used with essentially all 250°F (121°C) film adhesives and has been designed to provide optimal structural performance at temperatures ranging from -67°F to 300°F (-55°C to 149°C). BR 127 primer is formulated to provide maximum environmental resistance and durability within the bond line, as well as prevent corrosive undercutting. It can also be used effectively as a protective coating outside bonded areas. BR 127 corrosion inhibiting primer can be cured prior to bonding. Recommended cure cycles range from 4 hours at 180°F (82°C) to 30 minutes at 250°F (121°C). Articles primed with BR 127 primer and then cured have an indefinite shelf life. Primed details should be wrapped in Kraft paper (as protection from dust and dirt) and stored prior to adhesive bonding. Maintaining controlled conditions of 85°F (29°C) maximum temperature and 65% maximum humidity is recommended for extended storage life. Cure cycles for adhesive films primed with BR 127 primer may vary from 200°F to 350°F (93°C to 177°C) with minimum pressures to assure proper mating of bonded details.
If necessary I can take off this primer at the bond line with Garnet right before gluing , because I think the glue I am using has a higher peel strength But then I expose myself to corrosion if the glue is not properly spread.
B.E.

You are judged not by what you know, but by what you can do.

 

[berkshire]

Ok I have now found a couple of companies that will Etch alodine and otherwise prep Aluminum panels for Adhesive bonding. One in Temecula Ca ,and one in Ontario Ca.

The particular Adhesive I intend to use was formulated by Dexter who later got taken over by Hysol , then Henkel , and now Loctite corporation and was used room temperature cure for fabricating patching and repair on several sailplanes, which I primarily work on, it was also used for repair on Grumman American light aircraft . It has been around the block since about 1974 so as Will says it is an old formulation.
B.E.

You are judged not by what you know, but by what you can do.

 

[WKTaylor]

Wow.. Temecula CA... it has gone from a sleepy village Off I-15, to a full-blown City in the last 40+ years...

Long ago [1968] My folks owned property and built and airstrip... Ernst Field... ~22-Miles E-N-E of Temecula City-center... just past the rural village/fire-station of Sage.

https://www.google.com/maps/place/T...03806a8!8m2!3d33.4936391!4d-117.1483648?hl=en

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[berkshire]

Yes Will it has ,
The old down town Temecula airport has gone, replaced by a huge shopping center. The city built a new airport at French Valley. The job I will be doing if I can get my ducks in a row will be at Lake Elsinore Airport . I used to fly not far from Ernst field at Hemet.
B.E.

You are judged not by what you know, but by what you can do.

 

[berkshire]

WKTaylor,
Will I looked up your family airport to find that it is still active , it goes by the designator 86CL and is privately owned with two aircraft on the field.
B.E.

You are judged not by what you know, but by what you can do.

 

[WKTaylor]

It's been a long-time. Sis & I miss the simplicity of 'the ranch'.

Folks sold-out +25-years ago, ~when dad turned +70... way too much work for an old guy with no 'young' help.

NOTE: RE the link to Google-Maps image...

Follow-along the direction of the Runway to the NE... about 3/4-RW-length [~3000', past the 'obvious' end of the RW]... to an area where there is a maze of dirt roads... almost at the end of the valley. There is a large coastal oak tree [+80' span] followed by a monster oak that spans +120'[double-trunk]. I hope the owners appreciate the unique magnificence of those old-oaks.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[berkshire]

Will ,
I will have to drive out there some time and look. That is about 30 miles from where I live.

I did some more digging on the history of the high peel strength epoxy and found some information on its origins. It started life as Dexter 1410 High peel strength room temperature cure structural adhesive. Dexter then got taken over by Hysol so it became Hysol EA 9410 , it was later reformulated to take the asbestos out so it became Hysol EA9430 this a non certified asbestos free structural adhesive. Grumman American light aircraft, started using EA9410 (With the asbestos in it), in the fabrication of the Ga5 Cougar light twin, so Hysol came out with EA9309 which was a certified version of EA9410 . Then when the asbestos was taken out, it became EA9309NA ( NA is no asbestos.) which is a certified version of EA9430. Now they have played with it some more so the latest iteration is EA9309.3NA AERO .
Cheers ,
B.E.

You are judged not by what you know, but by what you can do.