Sanitary Silicone Akemi bright grey 12 and the smoothing time window
A silicone joint is not made good by extruding it — it is made good by tooling it. And for that you have a window of 10 to 15 minutes. After that the skin has formed, and every attempt at rework leaves marks that cannot be talked away.
Bright grey 12 is one of AKEMI's light greys in this range. One note that saves real money when reordering: AKEMI also lists light grey 09 as an independent shade. The English names sit close together; the shades do not. That is why colour number 12 appears throughout.
Application area
AKEMI® Sanitary Silicone is a special joint-sealing material for expansion and connecting joints in kitchens, living and sanitary areas on ceramic tiles. Approved for interior and exterior use. Excellent and durable adhesion on non-porous silicate materials: glass, glazed ceramics, tiles, clinker, glass ceramics, email, porcelain and aluminium.
Skin formation, smoothing, hardening: the three times that make the difference
10 to 15 minutes for smoothing. The manufacturer specifies: apply the product and smoothen within 10 to 15 minutes. Optimal smoothing is achieved with a smoothing rubber and smoothing agent. In practice this dictates a section length you can genuinely extrude and tool within that window — extrude 8 metres in one go and you end up working against the skin.
Approx. 15 minutes to skin formation (at 23 °C, 50 % relative air humidity). The masking tape must be removed before the skin forms, pulling in the direction of the joint. Wait, and you tear the edge off with it.
Approx. 2 mm per 24 hours hardening, depending on layer thickness, temperature and relative atmospheric humidity. The surface is tack-free after a short period — that is a long way from hardened through.
Two traps from the data sheet that end up visible in the joint: excess smoothing agent must be removed to avoid staining. And: do not apply the primer to visible surfaces — again to avoid staining.
The rest is boundary conditions: working temperature +5 °C to +35 °C, dry flanks, contact surfaces free of grease and dust. Cold lengthens the times, but it does not make the window arbitrarily large.
Technical data
| Colour |
bright grey 12 (AKEMI item number 40012) |
| Container |
1C-cartridge, 310 ml |
| System |
acetate cross-linked |
| Permissible total deformation |
20 % |
| Working temperature |
+5 °C to +35 °C |
| Temperature resistance |
-50 °C to +180 °C |
| Skin formation time (23 °C, 50 % RH) |
approx. 15 minutes |
| Hardening (23 °C, 50 % RH) |
approx. 2 mm per 24 hours |
| Shore A hardness / modulus |
~22 / 0.44 N/mm² |
| Storage |
5–25 °C, unopened at least 24 months |
Full characteristic values, test standards and processing instructions: see the manufacturer's Technical Data Sheet.
Consumption per cartridge
| Joint width x depth |
Metres per cartridge |
| 5 x 5 mm |
12 |
| 10 x 10 mm |
3 |
| 15 x 10 mm |
2 |
| 20 x 15 mm |
1 |
Application in brief
- Contact surfaces dry, clean, free of grease and dust; clean with AKEMI® Cleaner A (tiles, ceramics, glass, non-painted wood, metal) or Cleaner I (plastics, painted surfaces).
- Joint size min. 5 x 3 mm. Insert back-filling cords to avoid adhesion on three flanks: closed-cell PE in damp rooms and outdoors, otherwise open-cell PUR. Mask off the joint edges.
- Apply at +5 °C to +35 °C with dry flanks. Smoothen within 10–15 minutes using a smoothing rubber and smoothing agent; remove excess smoothing agent.
- Remove the masking tape before the skin forms, pulling towards the joint. Clean tools with AKEMI® Cleaner A.
Full instructions for use in the manufacturer's Technical Data Sheet.
Important restrictions
For professional use only. Not suited for porous, absorbent surfaces like natural and artificial stone — danger of discolouring in the marginal zone. AKEMI offers dedicated neutral cross-linked products for natural stone.
- Releases acetic acid during hardening — not on or near acid- or corrosion-sensitive materials (iron, copper, brass, zinc, lead, concrete, materials containing lime or cement).
- No sufficient adhesion on silicone, PE, PP, PTFE, butyl rubber, neoprene, EPDM or plasticised plastics.
- Discolouration on tar- and bitumen-coated surfaces as well as elastomers (EPDM, APTC, neoprene).
- On wood, metal, paints, plastics, stainless steel and sanitary acrylate no general prediction is possible — test adhesion and compatibility beforehand.
- Not for the construction of aquariums. Read the Safety Data Sheet.
Conformity
EN 15651-3 (XS1) · EN 15651-4 (PW20LM Ext.-Int.) · GEV EMICODE® EC1PLUS · VOC France emission class A+ · REACH compliant (EU No. 1907/2006) · IVD-leaflets 3-1 and 14.
Further colours in this range
Sanitary Silicone Akemi transparent 01 (Art. No. 16255) · Sanitary Silicone Akemi white 02 (Art. No. 16256) · Sanitary Silicone Akemi silver grey 05 (Art. No. 16259) · Sanitary Silicone Akemi pale grey 11 (Art. No. 16264) · Sanitary Silicone Akemi flannel grey 15 (Art. No. 16268) · Sanitary Silicone Akemi stone grey 17 (Art. No. 16270) · Sanitary Silicone Akemi sanitary grey 18 (Art. No. 16271) · Sanitary Silicone Akemi grey 22 (Art. No. 16275) · Sanitary Silicone Akemi anthracite 23 (Art. No. 16276) · Sanitary Silicone Akemi cloud grey 74 (Art. No. 16300) · Sanitary Silicone Akemi fog 82 (Art. No. 16304)
How much time do I have to smooth the joint?
10 to 15 minutes after application.
The manufacturer specifies applying the product and smoothening within 10 to 15 minutes. Skin formation time at 23 °C and 50 % relative air humidity is approximately 15 minutes. Divide longer joints into sections you can reliably complete within that window.
What is the difference between bright grey 12 and light grey 09?
Two distinct shades within the same AKEMI range.
The names sit close together, the shades are independent: bright grey carries number 12 (manufacturer item number 40012), light grey carries number 09 (manufacturer item number 40009). This article is exclusively bright grey 12. In German AKEMI lists bright grey 12 as "hellgrau 12" and light grey 09 as "lichtgrau 09" — there too, it pays to read the number rather than the name.
What should I use to tool the joint?
A smoothing rubber together with smoothing agent.
The manufacturer names this combination explicitly as the route to optimal smoothing. The second half of the instruction matters just as much: excess smoothing agent must be removed to avoid staining. What stays in the joint is intended — what stays beside it becomes visible.
When must the masking tape be removed?
Before the skin forms, pulling in the direction of the joint.
That is the manufacturer's instruction. Since skin formation begins after roughly 15 minutes under standard conditions, removing the tape follows practically straight on from tooling. Pull the tape later and the already skinned edge comes away with it — and the joint has to be redone.
Do you have any questions on this item?
