Gluing Robot Frames

[Trent B]

To branch off from Rion's thread here is a thread to discuss gluing frames which was initially brought up by IndySam as an alternative to welding the frame

Quotes from Rion's thread are the following.

Originally Posted by IndySam

<snip> We don't use welding anymore. Instead we glue everything together. Never had a failure.

Originally Posted by IKE

I would love to hear more about this.

Originally Posted by IndySam

We machine connectors (like 8020 quick frame) that slip inside the 1" square tube and then use Loctite Hysol to bond them together.

You can hit it with a sledge hammer and the aluminum will give way before the Hysol does.

Originally Posted by gburlison

Which Hysol formulation do you use? Epoxy, Urethane, or Polyurethane? Any other information about how you bond the aluminum frame together would be appreciated.

Originally Posted by Trent B

IndySam I am with gburlison in that I would love to hear more about this. I never thought of gluing a frame together but that may be a good alternative to welding as we have a sponsor who could get us the 8020 parts easily enough (if we can't make our own) Do you have any examples of possibly a 2x1 tube connector? If you don't I would still love to see what your 1x1's look like.

Thanks,

Trent

Originally Posted by rc_cola1323

Someone should really just start a new thread about this. I'm interested as well.

-RC

Originally Posted by Akash Rastogi

This isn't that uncommon of a practice guys, and its fairly easy to do even with 1x1 and 1x2 square tubing. We've done it for the past 3 years or so; however, we machine out nylon and UHMW (and even solid aluminum) blocks to insert into the ends of the tubing. Then simply rivet, screw, or bolt the block into place. The ends of the blocks (or wherever you need) are drilled and tapped. The screw or large rivets are easily replaceable with hard epoxy, loctite, or even gorilla glue (in some areas). And there you have a snug fitting frame connector!

I would like to see Pics of this in action too.

[scottydoh]

This is a very intriguing idea, never seen this before. But, I have a question about it...

In an emergency situation, how do you take these glued joints apart? If its welded conventionally, you just take out the grinder and its done. The epoxy seems a little more permanent seeing as they're saying the aluminum fails before the epoxy.

For this reason, 810 has never welded anything due to the fear of having to change out a damaged frame piece or make a last minute design change, which has happaned to us before.

[Al Skierkiewicz]

I have to ask the question as to how do you make repairs at competition sites?

[IndySam]

We have a meeting Monday afternoon and I will get some pictures and more details.

If you need to take a joint apart all you need is a good application of heat. We have done that with axles glued into support blocks.

As far as repairs go, we haven't had a frame failure in five years. We like to build our robot so we spend our time fixing other peoples machines instead of our own.

The standard repairs would apply. A good hacksaw or a trip to the welder for some heat application to separate the joint. Then either a welded repair or bolted repair. If there is a evening to allow the epoxy to set then re-gluing will work.

[MrForbes]

We glued and stapled our chassis together last year. But it was made of plywood, not aluminum

In the case of wood, you can use superglue to repair it relatively quickly. I don't know how effective that would be with metal, though.

[IndySam]

This is the building sketch from last years lower frame. The connector pieces were simplified because our machining capabilities were more limited last year. This year we have the machine shop teacher as one of our sponsors and his best students are lined up and excited about making parts for us so we can make connectors more like the quick frame pieces (wow that's a long sentence.)

You can see how we notched some of the pieces (kind of like Lincoln Logs) for assembly. We had more of these on the upper frame than the lower frame. These were hand fit and very strong when glued.

The holes you see are for 1/2" aluminum rod that connected the upper and lower frames together. Pictures I will take Monday will show this better. This may also change with our new machining capabilities.

[Dick Linn]

IndySam, which Hysol product are you using?

[IndySam]

Originally Posted by Dick Linn

IndySam, which Hysol product are you using?

It was the E series two part epoxy in the tubes. I don't remember if it was the CL or HP. I will have to check in the shop to make sure and get the exact part number.

[Dale]

I just started a thread on Connecting Quickframe because I didn't want to hijack this one on gluing. I would be interested in more detail/photos of how you notched those pieces that fit together like Lincoln Logs. Are those oversized pieces of aluminum or still Quickframe? If the later do you just bend the flaps out to go around the other member?

[IndySam]

These first two picture show the types of connections we used last year. You can also see where we later riveted in some 1/16 wall tube to support the electronics board.




This shows how we did the "Lincoln Log" type connections.




Last year we used E-20HP and E-60HP (the difference is working time.)
This year we recieved a case of E-30UT as a donation. This pick is a test of this product. Notice that the tube gave way and the epoxy never did.

[Tanner]

Kind of bizarre to see.

I guess you guys do CADD before doing any gluing?

-Tanner

[IndySam]

Originally Posted by Tanner

Kind of bizarre to see.

I guess you guys do CADD before doing any gluing?

-Tanner

Draw yes, CAD no. Not last year at least.

[its da PAT!!!]

This is what the product looks like that we used last year.

[Rohan J]

Our team uses machine screws and the normal Quickframe nylon connectors to secure the pieces together. For high stress applications, we sometimes drill a through hole and use a 10-32 bolt.

My question is, what is the advantage to the notched "Lincoln Log" system as opposed to adding another T joint? The Lincoln log system wouldn't work so well with standard Quickframe because of the rounded edges.

[Gdeaver]

In the picture, it looks like the used standard 1/8" wall tubing. I question doing this with 1/16" wall quick frame.