# Spot welds on Classics



## phario (May 7, 2017)

So with the usual discussions of old vs new models, I found the following interesting.

Here is a picture of a 2003 model. The bottom plate is held in only along various tabs and from what I have heard, it is common for these welds to break.




























On the other hand, here is a 2004 model. Yellow areas welded. Note the purple circle.










1. Does anybody have experience preempting weld failures? Would you need to use a welder or could you use something like JBWeld. @rattyI think you mentioned your experience with this but can you write a few words?

2. I noticed that the 2004 model has holes where you could insert a ~2.5mm machine screw and bolt and provide additional support. I may do this.


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## El carajillo (Mar 16, 2013)

The circles are machine made spot welds where two electrodes are brought together on opposing sides holding the metal together and passing a current through fusig the two components together. A car body shop MAY have this type of spot welder and do it for you .

Home type wire welders would need to run a seam where the two panels meet. BUT may cause distortion and colour change (blue burn mark)

CSK stainless screws / bolts or rivets would be easier / reinforcement


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## phario (May 7, 2017)

El carajillo said:


> CSK stainless screws / bolts or rivets would be easier / reinforcement


 In the case of the small tabs on the 2003 model, I assume that bolts or rivets would be very difficult because you'd have to predrill through the tabs. So you would have no choice but to do welding?

Thanks for noting the idea about the CSK bolts. It seems easy to add 4 bolts to relieve the stress on the front of the 2004 machine and to pre-empt any sagging.


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## Blue_Cafe (Jun 22, 2020)

I'd just glue them if they have failed.

If you go to your local motor factors there is a two pack metal adhesive which is sold and honestly, it could glue the Titanic back together. This is not your usual araldite shoite mind.

It's nuts.

You have good area for adhesive coverage (the most important thing here tbh) so you should get a really strong bond. A tickle with Emery and degreaser will help.

I use this in my car to repair broken bits and bobs and it will be there long after everything else has fell apart.

Or, strip the chassis and take it to the local body shop. They will have a spot welder and may do it cheap. You will need to polish up any visual surfaces though.

Edit: It's Stainless Steel structural adhesive.


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## ratty (Sep 22, 2019)

phario said:


> Does anybody have experience preempting weld failures? Would you need to use a welder or could you use something like JBWeld. @rattyI think you mentioned your experience with this but can you write a few words?
> 
> 2. I noticed that the 2004 model has holes where you could insert a ~2.5mm machine screw and bolt and provide additional support. I may do this.


 I've used JB metal weld on the back face behind the pump. The gap however is quite wide after the spot welds had broken that effectively hold the case under compression. The first attempt broke again when the pump was switched on so I found a feeler gauge the correct thickness to fill the gap (after removing as much of the hardened glue as I was able to!) and used the feeler gauge to bridge the gap and glued it between the two faces.

It worked that time.

But it maybe an idea to add some extra strength before they break, such as suggested by nuts and bolts, as welding stainless, even spot welding can cause distortion through heat retention on cooling, I guess that is why the spot welds fail as heat must be minimised, therefore producing a weaker join.

The best answer would be laser welding but costs would rule that out.


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## Blue_Cafe (Jun 22, 2020)




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## ratty (Sep 22, 2019)

Great idea using pop rivets.

The riveter gun would need to be pretty good for riveting stainless steel rivets, so probably a dearer model than used for aluminium rivets would be needed.

If you have the kit fine, and go ahead, as aluminium rivets are a definite no no, they would corrode fairly quickly due to galvanic corrosion of dissimilar metals.

Being a bolt man, I would drill a 3mm hole and use stainless steel dome head bolts, and use just two, as bolts are stronger than rivets.

https://www.ebay.co.uk/itm/M3-3mm-BUTTON-HEAD-SCREWS-ALLEN-KEY-HEX-SOCKET-DOME-BOLTS-A2-STAINLESS-STEEL/181024489629?hash=item2a25e6809d:g:cf4AAOSwj6lbvJDw

Will definitely go with the drill and bolt method next time, maybe on all of them even pre break?


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## ratty (Sep 22, 2019)

Should have made myself clearer!

What I meant is just two bolts on the back of the machine that seem to be the welds that usually fail, at least initially, probably due to pump vibration.

With these bolted in position it should lessen any strain on the side welds, hopefully enough to prevent further breakage.

Edit. As L&R says in next post, locking the portafilter in position twists the body causing the weld failure - makes sense.


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## L&R (Mar 8, 2018)

Welds fail because of twisting of the body while securing in place portafilter, 2 A2 bolts will be fine and aesthetically acceptable. I usually use 2 component strong transparent epoxy glue. Unless you have good spot welding equipment welding is not a good idea IMO.


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## ratty (Sep 22, 2019)

So decided to give this a try using the dome head bolts mentioned.

I decided to use serrated flanged nuts as the serrations act as a locking action.

Just in case I didn't like the look of it, I also ordered some 9mm OD penny washers to maybe use on the inside of the machine in front of the nut, that did not arrive in the post today of course!

These are the nuts; (the £1.95 are for the pack of 20 nuts by the way!)

https://www.ebay.co.uk/itm/FLANGED-NUTS-TO-FIT-METRIC-BOLTS-SCREWS-A2-STAINLESS-STEEL-M3-4-5-6-8-10-12-16/150792649468?ssPageName=STRK%3AMEBIDX%3AIT&var=453878314860&_trksid=p2057872.m2749.l2649


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## phario (May 7, 2017)

Fantastic. Thanks ratty. I may do the same after disassembling the next time. I prefer bolts as well...not as nice but much more fixable and maintained.

Stupid question but it was no problem for you to measure and drill correctly? I am paranoid of mismeasuring--there is a fairly thin margin of error on drilling into that tab.

I learned the value of cobalt drill bits last time I made the pressure guage hole. Drilled for an hour using HSS vs a minute using cobalt!


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## ratty (Sep 22, 2019)

phario said:


> Fantastic. Thanks ratty. I may do the same after disassembling the next time.
> 
> Stupid question but it was no problem for you to measure and drill correctly? I am paranoid of mismeasuring--there is a fairly thin margin of error on drilling into that tab.
> 
> I learned the value of cobalt drill bits last time I made the pressure guage hole. Drilled for an hour using HSS vs a minute using cobalt!


 It's the old adage, measure twice and drill once or in my case measure six times, drill and cross fingers!

I use cobalt drills too. The 3 mm ones are reasonably priced. I have a couple of new ones so next time I need to drill I will use a new one.

This time the used one burst through the stainless and the drill chuck made a mark on the back face as it bumped it. I have ordered an Oxford eraser and will use it as a cushion between the back of the drill bit and drill chuck (cut down of course) cost a quid. The proper jobbie made of plastic so no damage caused, is;

https://www.amazon.co.uk/Century-Drill-73512-Adjustable-Piece/dp/B003L0XB8Y/ref=sr_1_fkmr0_1?dchild=1&keywords=Century+Drill+%26+Tool+73512+Adjustable+Drill+Stop+-+MADE+IN+USA&qid=1597994067&sr=8-1-fkmr0

And costs over £8 with postage


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## Fantik24 (Oct 13, 2021)

These circles are essentially spot welds that remained after they were machine-welded, where there were two electrodes brought together at two opposite ends. It turns out that this design held the metal together and passed current through the fusion of the two components together. There may be such a spot welding machine in the auto repair shop and you can contact them, I think they will help you. But I know for sure that such a welding machine is used by welders of the highest ranks. Look here https://weldingnearyou.com / maybe you will find some useful information. I wish you good luck and success in your business.


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