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Gasket Material for an Air Compressor

Gasket for a Blackspur AC150 Air Compressor

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Halton Tank02/01/2013 21:44:24
97 forum posts
56 photos

Some years ago I had problems with my compressor where some material a got sucked in the air intake. To clear this I had to take the cylinder head off. In the process the gasket broke. The original gasket was made from a soft aluminium alloy, but in order get thing working I made a temporary paper gasket whilst I tried to get a replacement gasket. As it is common with me things on the 'to do' list did not happen.

Recently the compessor was struggling to reach pressure and on examination I have found the gasket has blown. Trawling through the net I found that Blackspur Tooling who supplied the compressor are no longer in existance and nor I could easily find any altenative spares supplier.

As my temporary gasket lasted at least five years I might as well make another gasket. I was wondering are there better materials that I could use instead of gasket paper.



Jeff Dayman02/01/2013 22:07:31
2165 forum posts
45 photos

Loctite 30511 form-a-gasket and a thin aluminum sheet same thickness as the original alum gasket would get my vote. Use a thin layer of the 30511 on both sides of the alum gasket/spacer and it will likely last forever. The 30511 is good to 400 deg F and is oil, gasoline, solvent and water resistant. Make sure to use the minimum amount of sealer - too much and it could interfere with the air valves.

If the orig alum gasket was less than about .008" thick, just the 30511 compound would likely work on its own. However if the orig alum gasket is say .020" to .060" thick or thereabouts, it probably acts as a spacer in the head assy and should be replaced by something of a similar thickness.


Siddley03/01/2013 00:04:58
150 forum posts
1 photos

I sometimes used to cut gaskets from copper sheet for my British bikes and that worked OK if you annealed the copper afterwards.

If it's OK for a pre-unit Triumph Bonny engine with 10.5-1 pistons it'll probably be OK in an air compressor

Roger Mountain03/01/2013 01:31:49
14 forum posts
8 photos

My compressor did the same, I cut one from copper sheet using a piercing saw. Anneal the gasket by heating to cherry red then quenching, check that the head is flat and if not address the matter with a flat surface and some wet & dry. Mine has given no trouble since.

Regards, Roger

Russell Eberhardt03/01/2013 10:50:20
2695 forum posts
86 photos

Have a look here for proper gasket paper:


It's cheap, very tough, and designed for the job. The graphited material is tougher but rather expensive.


Halton Tank04/01/2013 11:23:42
97 forum posts
56 photos

It seems that copper is the best way to go. Had a quick look in the workshop a found some 1/16" thick copper sheet of suitable size, or should I go for something thinner/thicker. Unfortuneately I cannot remember how thick the original gasket was.

Many thanks to those who replied.


Ian S C04/01/2013 13:26:57
7468 forum posts
230 photos

Luigi, I'd use the copper, cut it out, and anneal it, it does not matter if you quench it or not, it does not effect the heat treatment, just speeds up the time for picking it up. Ian S C

landlubber06/01/2013 21:36:21
2 forum posts

Hi Guys, first post but I have been following the forum from the start.

I also have a problem with a compressor but different to above, it does not seem worthwhile starting a new thread.

I was given the compressor as it was going for scrap, it turned pout to be an easy fix and still OK for a home workshop. Antway it works but when switched off will not hold the pressure in the tank.

It has a 300 litre (ish) tank with a "mudhole" door. It appears to be leaking from here, although I need to run some gas leak fluid around the joint to confirm this.

Does anyone know if the door will be metal to metal with the tank or will it have a gasket.............if so any suggestions for material to replace has no manufacturers name or any other identification marks!!!

happy new year to all


Ian S C08/01/2013 00:52:11
7468 forum posts
230 photos

norman, I'd try loctite liquid gasket rather than trying to make a gasket for the job. Ian S C

Russell Eberhardt08/01/2013 13:16:02
2695 forum posts
86 photos
I was given the compressor as it was going for scrap, it turned pout to be an easy fix and still OK for a home workshop. Antway it works but when switched off will not hold the pressure in the tank.

It has a 300 litre (ish) tank with a "mudhole" door. It appears to be leaking from here, although I need to run some gas leak fluid around the joint to confirm this.

With an old compressor of unknown history like this I would advise getting a hydraulic test to 2x working pressure. If it ruptures, a tank this size can have nasty consequences.


Halton Tank07/02/2013 22:28:19
97 forum posts
56 photos

Finally I managed to get back into the workshop after Christmas and stewarding at the LMEE at Ally Pally and to ease myself in I decided to fix the compressor. At my club's metal store I managed to find some thinner copper sheet (around 24 thou) than what I had. After cutting out the gasket I annealed it and fitted it to the compressor with thin smear of liquid gasket. Fired up the compressor and it worked a treat reaching max pressure under 5 minutes.

Now the lawn mower can get a clean after use.

Thanks to all for their suggestions.


DMB07/02/2013 23:10:31
1154 forum posts
1 photos


Your compressor reservoir is of uncertain age/condition. It could be as rusty as hell inside where you cannot see it and about to "blow." You are playing with a potential BOMB! Get it fixed (tested) pronto before it fixes you!

Take (more) care + good luck


I.M. OUTAHERE08/02/2013 04:55:03
1468 forum posts
3 photos

I agree with getting your tank tested but still cannot understand why you don't have to considering it can kill just as easily as a small boiler taking into consideration the difference in the expansion of steam versus compressed air etc .

If it were a boiler you would legally have to get it tested and in industry it would be yearly , here we have to have any compressor other than domestic use done yearly also .

You can get it tested with ultrasonics which will give a general idea of its condition but a pressure test is the best .

You also need to get the pressure relief valve checked as it could be faulty .

I know it costs money but i would rather spend the money on maintaining my equipement rather than paying for my funeral or even worse some one elses !

A copper gasket will be easier to make and anneal as you can see when it is red hot .

You can use soap as an indicator as to the heat level in alluminium , just smear it on and heat from the other side - when it ggoes black and burns it is hot enough .

You can also blacken it with the soot from an oxy torch ( don't breath in the soot as it can cause cancer ) then heat until the soot burns off which is close to melting point .

With the leaky mud door it will depend on whether it is a corrosion problem or if it is warped .

Corrosion - i would recommend getting rid of it as it is most likely corroded elsewhere .

Warped - i would be asking the question how it has happened ?

If the door has never been opened it should not be leaking so it could be a warning as to an impending failure .

If the door was opened then why ?

When buying a new unit please ensure that it meets or exceeds your local manufacturing / safety standards as there are some dodgy pieces out there .

Oh and by the way EVERY time you start up the compressor give the blow of valve a tug to ensure it is not frozen - same goes for water heaters give the pressure relief a a tug here and there as they too can flatten a house !


Halton Tank08/02/2013 16:45:09
97 forum posts
56 photos


I think you have confused Norman's (landlubber) with mine. I do know the history of my compressor as I bought it new in 2004, whereas Norman aquired his second hand. Generally I always blow the tank down when I have finished with the compressor so I suspect there has been little corrosion in the time I had the compressor, though I accept I really should get the tank examined.

I also suspect the majority of posters on this forum that own compressors have never had theirs tested since they had aquired them.


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