Welding Crack in Mosquito Slide?

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#1
I just received a used SIG Mosquito I got in a Gunbroker auction. While thoroughly cleaning it before taking it to the range, I saw that the back of the slide is cracked.

My first step was to tell the gun shop in Florida about the problem, and emailed a couple pictures. I'm awaiting a response.

crack_external_view_3368.jpg crack_internal_view_3367.jpg

The second step was to call SIG and ask about repairs. The answer is $155 (including shipping) and they don't have any more black slides available; just some camo job. They insist that the complete pistol be sent because slides have to be fitted. (Huh?)

While awaiting answers, does anyone weld an aluminum-zinc (I believe) crack? (I suspect not, but have to ask.)

Thank you,
Richard
 
Jan 2, 2018
71
23
8
#3
Aluminum zinc alloys aren't weldable. That would be the 7xxx series of Al . The other non weldable Al alloy is the 2xxx series alloyed with copper. They can be braised or soldered. 7000 series Aluminum is the strongest of the group and stronger (but more brittle) than some mild steels.

1xxx, 3xxx, 4xxx, 5xxx and 6xxx series Aluminum alloys are weldable.

Sorry for your misfortune, hopefully there is a means of correction back at the seller. Good luck.
 

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#5
Aluminum zinc alloys aren't weldable. That would be the 7xxx series of Al . The other non weldable Al alloy is the 2xxx series alloyed with copper. They can be braised or soldered. 7000 series Aluminum is the strongest of the group and stronger (but more brittle) than some mild steels.

1xxx, 3xxx, 4xxx, 5xxx and 6xxx series Aluminum alloys are weldable.

Sorry for your misfortune, hopefully there is a means of correction back at the seller. Good luck.
Thank you for the informative answer. This is what I suspected.

I had considered brazing, but feel it would heat too much of the slide and destroy any heat treatment it might have had. Or just melt the discouraging alloy.

I hope I'll be able to return it for a refund. I got it for my brand-new daughter-in-law who really likes the Mosquito. Heck, with a refund, I could get her a new Firefly -- same pistol, same manufacturer.

Thank you,
Richard
 

diverdon

Online Training Member
Dec 21, 2011
2,594
672
113
WNY
#6
Sorry, I'm not that wealthy.
Sig did a lot of damage to there brand trying to make a quick buck on this. I've never seen anyone who has one purchase another Sig. Sorry I don't know anything useful that can be done with it.
 

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#7
Sig did a lot of damage to there brand trying to make a quick buck on this. I've never seen anyone who has one purchase another Sig. Sorry I don't know anything useful that can be done with it.
As I mentioned in reply to another post, I got this because my daughter-in-law likes it. Having closely examined this pistol, I'm afraid I tend to agree with your evaluation. I'm just stuck with returning it if possible, or spending more money to fix it if, for whatever reason, the dealer won't accept its return.

Cheers,
Richard
 
Likes: diverdon

GH41

Sergeant
Mar 18, 2014
393
7
18
#9
As I mentioned in reply to another post, I got this because my daughter-in-law likes it. Having closely examined this pistol, I'm afraid I tend to agree with your evaluation. I'm just stuck with returning it if possible, or spending more money to fix it if, for whatever reason, the dealer won't accept its return.

Cheers,
Richard
If the seller won't refund your money I would also recommend throwing it away. I wouldn't spend money fixing something that might crack again next week. It is a very common problem.
 

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#10
If the seller won't refund your money I would also recommend throwing it away. I wouldn't spend money fixing something that might crack again next week. It is a very common problem.
Throw it away. I'm apparently in the midst of a group of very wealthy people. Can I interest you in adopting me?

Cheers,
Richard
 

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#12
'Fraid I paid by personal check. Shall see if the shop offers a refund. If not, I at least will file a complaint with Gunbroker, and possible the BBB.

Thank you,
Richard
 

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#14
This was a shop? Hard to believe that they did not know it was damaged. That’s fraud. If they shipped it US Postal that’s mail fraud.
Will see what the owner says on Monday.
I will say that the crack was not noticeable until the slide had been thoroughly cleaned. Until then, some old grease/dirt/powder had done a fine job of camouflaging it.
When you get right down it, if getting a refund fails, I may just keep the pistol and flog the heck out of it. The crack isn't through the slide; where it is shouldn't affect functioning at all.

Cheers,
Richard
 

GH41

Sergeant
Mar 18, 2014
393
7
18
#15
Throw it away. I'm apparently in the midst of a group of very wealthy people. Can I interest you in adopting me?

Cheers,
Richard
I might be interested in adopting you. Do you do floors? Cook? My wife does neither and cost me a fortune! I'll tell you what.. I'll let you adopt her. For every week you keep her I'll buy you a Sig Mosquito as long as the supply last. That would be the best business deal I have ever made!!!
 

Max

Descendant of John Adams
#16
Will see what the owner says on Monday.
I will say that the crack was not noticeable until the slide had been thoroughly cleaned. Until then, some old grease/dirt/powder had done a fine job of camouflaging it.
When you get right down it, if getting a refund fails, I may just keep the pistol and flog the heck out of it. The crack isn't through the slide; where it is shouldn't affect functioning at all.

Cheers,
Richard
Well let’s hope they just goes good on it, 🤞
 
Feb 20, 2011
26
1
3
46
Coatesville, Indiana
#17
That repair would be a no-go even if the alloy was weldable. With a standard 50% de-rate due to heat input and HAZ, it would fail sooner than later. That's not even mentioning warping. AL loves to heat warp and shrink and pull all over the place.
 

rg1911

Gunny Sergeant
Oct 24, 2012
531
10
18
65
Laramie, Wyoming
#18
The Mosquito was shipped back today for a full refund (at least that's what the shop wrote).

Thanks for all the good information that convinced me to not mess with it.

Cheers,
Richard
 
Jan 2, 2018
71
23
8
#19
Oh I forgot about that, whatmeworry is correct, aluminum loses around half it's strength when welded. That's why vehicles made out of aluminum are riveted together instead of welded seams. Welding is the process of taking your perfectly machined parts and destroying them with heat. Can't recall the number of parts I've destroyed through either heat-treat or welding ops after machining.

to the OP, good to hear they are making right on it.
 
Jun 1, 2009
195
15
18
Mississippi
#20
I had a Mozzie years back but sold it in favor of a threaded .22 conversion for my 226. As for welding, all that about aluminum losing half it’s strength when welded, that’s news to me and a lot if boat builders. Austal Shipbuilding builds aluminum welded high speed ferries and littoral combat ships for the navy. Also, a lot of Coonasses built welded aluminum boats that take quite a beating. I think riveted aluminum boats are in the weaker camp. I forgot who made the welded aluminum suppressor back about 8 years ago but if I recall it was pretty tough. Now a Mozzie slide is a different animal. Put it on a scrap heap with the early P22s.
 
Jan 2, 2018
71
23
8
#21
As for welding, all that about aluminum losing half it’s strength when welded, that’s news to me and a lot if boat builders. Austal Shipbuilding builds aluminum welded high speed ferries and littoral combat ships for the navy. Also, a lot of Coonasses built welded aluminum boats that take quite a beating. I think riveted aluminum boats are in the weaker camp. I forgot who made the welded aluminum suppressor back about 8 years ago but if I recall it was pretty tough.
https://www.sciencedirect.com/science/article/pii/S2092678216302849 Pretty good paper describing alum welding with boat construction. Structural Allowances are made to make up for the loss of strength in the welded joints. Steel welds have much better bonding and crack resistance. Tempering and work hardening of alum materials gets tricky, it's all about the T state that you need when finished. you guys that weld aluminum my hat is off to you!
 

hermosabeach

Confused Coffee Drinker
Feb 13, 2012
2,775
1,868
113
78
#22
Assuming Sig denies the warranty claim as you are not the original owner
Assuming the FFL and the shipper deny the claim-


Does the crack impact function? Can you drill the end of the crack to keep it from spreading and then repair when the budget allows?
 
Top Bottom