Welcome, Guest. Please Login or Register

Author Topic: cast aliminium bash plate  (Read 14283 times)

0 Members and 1 Guest are viewing this topic.

Offline Sláinte Mhaith

Re: cast aliminium bash plate
« Reply #20 on: May 24, 2015, 09:33:14 am »
No! Do not diy a cast one... :deal:
Cast aluminuim does not have the tensile strenght plate has.
The metalurgists on the group will explain why. :sip:

From the little I learned and the less I know now (not a metallurgist either by a long shot)

Casting will have a granular structure while wrought plate will have a long grained structure.
In my mind it is like gluing lots of small balls together vs gluing small sticks together. You can imagine how the sticks will be stronger.
Similar to cast iron vs steel the first will be brittle.

So my guess is a cast bash plate will most likely crack and/or break instead of deforming.

Subscribe
 

Offline Welsh

  • BMW R1150GSV
  • Bachelor Dog
  • *****
  • Bike: BMW R1150GS
    Location: Gauteng
  • Posts: 18,423
  • Thanked: 534 times
  • Thunder Twonk. The two legged Twat Monkey.
Re: cast aliminium bash plate
« Reply #21 on: May 24, 2015, 12:30:33 pm »
Pressed, fabricated or forged, if cast was strong enough you would not need a bash plate as cast cases would be strong enough. It's about elongation before it breaks.
When is this "Old enough to know better" supposed to kick in?
 

Offline 2StrokeDan

  • a Man of Character
  • Castrated Dog
  • ******
  • Bike: KTM 690 Adventure
    Location: Western Cape
  • Posts: 24,448
  • Thanked: 1742 times
  • Slim like Bill, straight like Steve
Re: cast aliminium bash plate
« Reply #22 on: May 24, 2015, 06:08:50 pm »
Pressed, fabricated or forged, if cast was strong enough you would not need a bash plate as cast cases would be strong enough. It's about elongation before it breaks.

A lot of alluminium alloy frames has cast joints and steering head pieces in them, of course these are substantial in thickness.
 

Offline adamktm

  • Senior Member
  • ***
  • Bike: KTM 690 Adventure
    Location: Western Cape
  • Posts: 512
  • Thanked: 9 times
Re: cast aliminium bash plate
« Reply #23 on: May 24, 2015, 07:46:18 pm »
Looking forward to seeing how it turns out!!
2018 KTM 250 6 Days TPI
2011 690 Enduro

When I bleed, I bleed orange!
 

Offline shanti

  • Senior Member
  • ***
  • Bike: Honda CRF-1000L Africa Twin
    Location: Western Cape
  • Posts: 1,142
  • Thanked: 11 times
  • rest stop moon
    • derek saul
Re: cast aliminium bash plate
« Reply #24 on: May 24, 2015, 09:10:05 pm »
will post some pics as it goes , I'm going with the good deflection due to rounded shape and figuring a casting of 5mm is bound to be strong enough + soft enough to absorb/protect from rocks etc , I might be wrong - how the hell do you do a strength check ?  ??? :biggrin:

Offline Gérrard

  • AKA 'jupiter' maar noem my Gerard.
  • Global Moderator
  • Castrated Dog
  • ***
  • Bike: BMW R1200GS Adventure
    Location: Eastern Cape
  • Posts: 32,644
  • Thanked: 543 times
  • HKGK !!!
Re: cast aliminium bash plate
« Reply #25 on: May 25, 2015, 08:43:08 am »
will post some pics as it goes , I'm going with the good deflection due to rounded shape and figuring a casting of 5mm is bound to be strong enough + soft enough to absorb/protect from rocks etc , I might be wrong - how the hell do you do a strength check ?  ??? :biggrin:

Remember Thomas Edison, and how many times he tried, and failed, before he got the light bulb to work. If he did not try and fail we would not have had lights.

Make a rough tester and moer it with a 5pd hammer. Remember, impact that is not absorbed, is transferred somewhere else.
...dis nooit te laat om n happy childhood te he nie !

Build a sidecar they said. It will be fun they said. Ja-nee !
 

Offline lecap

Re: cast aliminium bash plate
« Reply #26 on: May 25, 2015, 12:41:40 pm »
Pressed, fabricated or forged, if cast was strong enough you would not need a bash plate as cast cases would be strong enough. It's about elongation before it breaks.

In parts like cast frame members or swing arms you have well defined forces below the yield strength of the material.

Most impacts into the sump guard cause forces well in excess of the materials yield strength. You need a material which is ductile on the one side (it absorbs energy by deforming and allows a high amount of elongation before it tears) and has good shear strength on the other side (a rock will not tear a triangle shaped hole).
I found sump guards from 4mm 5083 sheet to work very well and the sheet is readily available and quite corrosion resistant.
The putty soft architectural grade stuff is useless.

A cast bash plate will crack and shatter just like eth engine you are trying to protect.
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." (Red Adair)
 

Offline shanti

  • Senior Member
  • ***
  • Bike: Honda CRF-1000L Africa Twin
    Location: Western Cape
  • Posts: 1,142
  • Thanked: 11 times
  • rest stop moon
    • derek saul
Re: cast aliminium bash plate
« Reply #27 on: May 25, 2015, 01:19:38 pm »
day is moving along slowly - against all logic (even my own after doing some reading and reading the replies) decided to give it a go , started my day with some urgent sculpture work ( gotta get paid for messing around ) now busy with the mould should have something cast at the end of the day to beat up with some hammers

Offline the_BOBNOB

  • is not a
  • Forum Whore
  • ****
  • Bike: KTM 990 Adventure
    Location: Western Cape
  • Posts: 8,614
  • Thanked: 168 times
Re: cast aliminium bash plate
« Reply #28 on: May 25, 2015, 01:32:11 pm »
looking good  :thumleft:

i'd like to see the end product, i think it will work

you can also add some fibreglass on the inside of the when its done - that should enforce it - in the end if it cracks it did its job - it protect your casing

if something hits it that hard that it can punch through it, through some fibreglass or rubber enforcing and then still break your casing you are screwed anyway  ;D
 

Offline Titanic

  • Senior Member
  • ***
  • Bike: BMW F800GS
    Location: Gauteng
  • Posts: 1,546
  • Thanked: 1 times
  • Life begins at 260.
Re: cast aliminium bash plate
« Reply #29 on: May 25, 2015, 01:38:24 pm »
Shanti
Sorry for hi-jack.
When you are done with this project, why don't you have a look at the following? It might be easy for you to make us something similar.
Mirror/choke relocation bracket for the KLR
http://www.eaglemike.com/Choke-and-mirror-relocation-bracket-cmrb.htm
 

Offline growweblaar

  • Senior Member
  • ***
  • Bike: BMW F800GS
    Location: Western Cape
  • Posts: 2,729
  • Thanked: 9 times
  • Somerset West
Re: cast aliminium bash plate
« Reply #30 on: May 25, 2015, 01:47:27 pm »
Interesting experiment! Subscribe.

I suspect it will shatter if you hit a rock hard, but perhaps fine otherwise...?

Have a look at this table comparing different alu alloys, magnesium, zinc & cast iron for casting. Yours would be in the S/SM column, since you're sand casting.

 :thumleft:
« Last Edit: May 25, 2015, 01:48:11 pm by growweblaar »
 

Offline shanti

  • Senior Member
  • ***
  • Bike: Honda CRF-1000L Africa Twin
    Location: Western Cape
  • Posts: 1,142
  • Thanked: 11 times
  • rest stop moon
    • derek saul
Re: cast aliminium bash plate
« Reply #31 on: May 25, 2015, 05:52:08 pm »
cast the plate - last cast for the day , foundry work is hardest on Mondaze for everyone - will take a look tomorrow better - although I couldnt resist swinging a hammer at it - slight dent but cant trust that as a test for a 50km wack - still figuring deflection is this plates strength - thanks for that table - would be interesting to see what the heattr is ( heat treatment ? ) I will consider casting smaller items Titanic - I am an artist so dont have much in the way of machining in my workshop . I think for the finer items perhaps doing a lost wax casting might be better - i get good results with my bronzes with very small tolerances , can pick up a finger print in the wax if I pay attention  - of course there is always shrinkage to be accounted for - will carry on tomorrow 

Offline shanti

  • Senior Member
  • ***
  • Bike: Honda CRF-1000L Africa Twin
    Location: Western Cape
  • Posts: 1,142
  • Thanked: 11 times
  • rest stop moon
    • derek saul
Re: cast aliminium bash plate
« Reply #32 on: May 25, 2015, 05:55:15 pm »
I did modify the original plastic bashguard by removing the lower holes and adding a strengthening to the base , those familiar with the plastic bashguard will notice the difference

Offline Welsh

  • BMW R1150GSV
  • Bachelor Dog
  • *****
  • Bike: BMW R1150GS
    Location: Gauteng
  • Posts: 18,423
  • Thanked: 534 times
  • Thunder Twonk. The two legged Twat Monkey.
Re: cast aliminium bash plate
« Reply #33 on: May 25, 2015, 06:01:19 pm »
Impressive... really cool  8)
When is this "Old enough to know better" supposed to kick in?
 

Offline Sláinte Mhaith

Re: cast aliminium bash plate
« Reply #34 on: May 25, 2015, 06:40:08 pm »
 

Offline Crab

  • Senior Member
  • ***
  • Bike: Suzuki DR650
    Location: Eastern Cape
  • Posts: 2,010
  • Thanked: 7 times
Re: cast aliminium bash plate
« Reply #35 on: May 25, 2015, 07:26:05 pm »
Looks good so far
Look for a shooting star and see Lynda's trail and remember all the great places you shared with her,she will never forget what she shared with you and will show you that in every starry night .
 

Offline Weedkiller - Adie

Re: cast aliminium bash plate
« Reply #36 on: May 25, 2015, 08:01:50 pm »
Bliksem
so leer ons elke dag iets nuut

Adie
Laat ons Stof maak.
 

Offline zacapa

  • Senior Member
  • ***
  • Bike: Honda XR650L
    Location: Kwazulu Natal
  • Posts: 2,067
  • Thanked: 61 times
  • XR650L - 134.217kg lite weight special...
Re: cast aliminium bash plate
« Reply #37 on: May 25, 2015, 08:23:01 pm »
nice thread with some counter intuitive angles. then again I bought an XR650L which is so high off the ground there is little need for a bashplate in the first place.
 

Offline capeklr

  • Senior Member
  • ***
  • Bike: BMW R1200GS Adventure
    Location: Western Cape
  • Posts: 1,206
  • Thanked: 8 times
Re: cast aliminium bash plate
« Reply #38 on: May 25, 2015, 08:51:32 pm »
I like, I see it comes complete with centre stand.  >:D
 

Offline shanti

  • Senior Member
  • ***
  • Bike: Honda CRF-1000L Africa Twin
    Location: Western Cape
  • Posts: 1,142
  • Thanked: 11 times
  • rest stop moon
    • derek saul
Re: cast aliminium bash plate
« Reply #39 on: May 25, 2015, 08:54:26 pm »
havn't you seen the aquaplaning farkle for the KLR yet ?